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Recent problems solved by 'shahid'
shahid answered: 44 problems
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Volume/145772: If each demention of a box is quadrupled, how are the surface area and volume affected? 1 solutions
Answer 106385 by shahid(44) on 2008-06-19 12:52:38 (Show Source):
You can put this solution on YOUR website!let L,W,H be the dimensions of the box then volume= L x W x H=LWH now if we each of the dimension is quadruppled new dimension will be 4L,4W,4H so volume will be V=4L x 4W x 4H=64LWH so volume is increased by 64 times the original volume.
similarly surface area = 2(LW+LH+WH)
new surface area = 2(16LW+16LH+16HW)
=32(LW+LH+HW) surface area increased by 32 times
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Angles/145352: Find the measure of an angle if its measure is four times the measure of its complement???? 1 solutions
Answer 106031 by shahid(44) on 2008-06-15 03:17:21 (Show Source):
You can put this solution on YOUR website!consider x as an angle then its complement will be 90-x follow the condition
x=4(90-x)
x=360-4x
x+4x=360
5x=360
x=360/5
x=72 deg so angle is 72 deg.
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Rectangles/145162: Suppose the length of a rectangle is 3 inches longer than the width and that the perimeter of the rectangle is 78. Which I figured that out the length of the rectangle is 21 inches and the width is 18 inches. The next question asks "Set up and equation involving only W, the width of the rectangel?" I am not sure what that is asking??? 1 solutions
Answer 105845 by shahid(44) on 2008-06-13 04:10:43 (Show Source):
You can put this solution on YOUR website!if W is width then length will be W+3 now we know that perimeter is given by formula P=2L+2W
so P=2(W+3)+2W
78=2W+3+2W
78=4W+3 that is the equqtion of W
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Travel_Word_Problems/145072: two cars leave town at the same time going in the same direction. One travles at 50 mph and the other travels at 70 mph. In how many hours will they be 60 miles apart? 1 solutions
Answer 105755 by shahid(44) on 2008-06-12 04:02:19 (Show Source):
You can put this solution on YOUR website!as both cars going in same direction so net velocity =(70-50)=20 mph
distance=60 miles use this fomula
Distance = velocity x time
60 = 20 x time
time = 60/20
time=3 hours
two cars will meet after 3 hours
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Travel_Word_Problems/145016: a rental car agency charges $14 per day plus 9 cents per mile to rent a certain car. another agency charges $19 per day plus 6 cents per mile to rent the same car. hom many miles will have to be driven for the cost of a car from the first agency to equal teh cost of a car from the second agency? round to nearest hundredth mile 1 solutions
Answer 105754 by shahid(44) on 2008-06-12 03:49:48 (Show Source):
You can put this solution on YOUR website!let x miles be the distance travelled by a car
rent by first company = (14+ 9x/100) in dollars
rent by second company = (19 + 6x/100) in dollars
follow the condition
14+9x/100=19+6x/100
9x/100-6x/100=19-14
(9x-6x)/100=5
3x=500
x=500/3
x=166.66 or x=167 miles approx.
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Inequalities/145013: Asked to graph the ineguality 3x1 solutions
Answer 105721 by shahid(44) on 2008-06-11 15:25:44 (Show Source):
You can put this solution on YOUR website!form an equation out of inequality 3x=-4y-4 or 3x+4y+4=0 draw graph of this then check this at origin if it satisfies the inequality then shed the region containing origin(0,0) otherwise shed other side of origin
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Miscellaneous_Word_Problems/145012: Solve:
If an object is thrown upward with an initial velocity of 64ft/sec, its height after t sec is given by h=64t-16t^2. Find the number of seconds the object is in the air before it hits the ground.
Any assistance you can provide me with is greatly appreciated! 1 solutions
Answer 105719 by shahid(44) on 2008-06-11 15:19:33 (Show Source):
You can put this solution on YOUR website!if height of the object is given as a function of time so its derivative gives velocity.as ball is thrown upward so its final velocity will be zero or dh/dt=0
differentiate h=64t-16t^2 w.r.t
dh/dt= 64-32t put dh/dt=0
64-32t=0
t=2 seconds.ball takes 2 seconds to attend maximum height and 2 seconds to return so total 4 seconds it remains in the air
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Functions/145000: PLEASE HELP
If the graph of f contains the points ( -1, 3), ( 0, 4) and ( 2, -7) list the points that would be found on the graphs of each of the following functions:
a) f (x – 3)
b) f (x) + 3
Thank You
1 solutions
Answer 105707 by shahid(44) on 2008-06-11 14:40:12 (Show Source):
You can put this solution on YOUR website!a)f(x-3)
from given points we get f(-1)=3 , f(0)=4 and f(2)=7
take x-3=-1 then x=2 so point (-1,3) corresponds to (2,3)
similarly (0,4) gives (3,4) and (2,7) gives (5,7) in this way we got these three points lying on the graph
b)f(x)+3 now consider h(x) such that
h(x)=f(x)+3 if x=-1 then
h(-1)=f(-1)+3
h(-1)= 3+3 since f(-1)=3
h(-1)= 6 so point is (-1,6) other points can be obtained by same
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Functions/144999: Determine the domain of f in f(x)=10- the square root of 3-x 1 solutions
Answer 105696 by shahid(44) on 2008-06-11 14:17:57 (Show Source):
You can put this solution on YOUR website!we define domain the set of all such values of x for which function has defined or finite value here f(x)= 10-  we look for the values of function for which it has defined value we know that square root of positive number exists only so 3-x>=0 or 3>=x or x>=3 hence all values of x are permissible except x<3 domain = all R except x<3
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Quadratic-relations-and-conic-sections/144997: In which direction does the hyperbola given by the equation below open? Check all that apply.
(y+7)^2/3^2 - (x-4)^2/7^2=1
i had originally put down but it came out wrong.
these are the possible awnsers...
A. Down
B. Up
C. Right
D. Left
1 solutions
Answer 105692 by shahid(44) on 2008-06-11 14:07:31 (Show Source):
You can put this solution on YOUR website!hyperbola always has two sheets if one sheet opens upward then other will open downward so there are almost two options either up and down or left or right
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Linear-systems/144989: two private airplanes travel toward each other from cities that are 780 miles apart at speds 190 mph and 200mph. they left at the same time in how many hours will they meet? solution__________ 1 solutions
Answer 105680 by shahid(44) on 2008-06-11 13:35:45 (Show Source):
You can put this solution on YOUR website!as the aeroplanes are coming towards each other so their speeds will sum up to get the total speed so (200+190)=390 mph since distance is 780 miles now use formula distance= speed x time
780 = 390 x time
time = 780/390
time = 2 hours
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Percentage-and-ratio-word-problems/144853: a totalk of $10,000 is invested in two funds paying 5% and 7% annual interest. the combined annual interest is $644. how much of the 10,000 is invested in each fund? 1 solutions
Answer 105562 by shahid(44) on 2008-06-10 16:32:53 (Show Source):
You can put this solution on YOUR website!let $x be invested at 5% then $(10000-x) be invested at 7%
now interest on $x at 5% will be = 
and interest on $(10000-x) = 
according to condition
5x/100+7(10000-x)/100=644
(5x+70000-7x)/100=644
-2x=100(644)-70000
-2x=64400-70000
-2x=-5600
2x=5600
x=5600/2
x=2800 hence 2800 is invested on 5% and 7200 on 7%
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Linear_Equations_And_Systems_Word_Problems/144849: a group of 80 people attend a ball game. there were four times as many children as adults in the group. write a system of equations that you could use to set up this problem, where a is the number of adults and c is the number of children in the group. solve the system of equations for c, the number of childern in the group 1 solutions
Answer 105561 by shahid(44) on 2008-06-10 16:04:00 (Show Source):
You can put this solution on YOUR website!80 people are there so first equation is
a+c=80....(1)
second equ formed by condition is
c=4a ....(2) subtacting both equations
a=80-4a
a+4a=80
5a=80
a=80/5
a=16 so c=4(16)=64 there were 64 children in the group
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Age_Word_Problems/144847: the sum of the ages of petra and her mother is 45. her mother is 9 years more than twice as old as petra. how old are petra and her mother 1 solutions
Answer 105557 by shahid(44) on 2008-06-10 15:38:31 (Show Source):
You can put this solution on YOUR website!let x years be the age of petra and y be the age of her mother.according to conditions
x+y=45 .......(1)
y=2x+9........(2) from this equ: y=2x+9 putting in equ:(1)
x+2x+9=45
3x=45-9
3x=36
x=12 putting this in equ:2
y=2(12)+9
y=33
hence petra's age is 12 and her mother's age is 33
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Vectors/144523: what the graph for 1/2(p+2)greater then or equal to 3/4(P-2) 1 solutions
Answer 105555 by shahid(44) on 2008-06-10 15:11:43 (Show Source):
You can put this solution on YOUR website!first take these values equal  = 
Now by cross multiplication
4(p+2)=6(p-2)
4p+8=6p-12
6p-4p-12-8=0
2p-20=0
p-10=0 dividing by 2
this is an equation of a line .In order to draw a graph we must have two variables connected by either equality or inequality sign.but if we consider a variable like q and take its values on vertical line then graph of above equation will be a vertical line otherwise a horizontal line be formed.as first value is greater than second value so p-10>0.hence graph contains the set of all points on the left of this line.
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Trigonometry-basics/144669: Hi, does anybody know the value of cot 90º? I think you would have to move counter clockwise from the standard position, but that would put you on top of the positive y-axis. Can anyone provide the answer and how they got it? 1 solutions
Answer 105547 by shahid(44) on 2008-06-10 14:28:03 (Show Source):
You can put this solution on YOUR website!cot90=0 it can directly be obtained from its trigonometric relation already proved which says that cotx=  .so we can get the value of cot90 from this formula.Now
cot90= 
cot90=  because cos90=0 and sin90=1
hence we have shown that cot90=0
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Polynomials-and-rational-expressions/144622: Some students planned for a get-together. The budget for food was $500. Five of the students failed to come because of the distance and therefore the cost of food for each member increased by $5. How many students attended the get-together?
1 solutions
Answer 105410 by shahid(44) on 2008-06-09 03:35:57 (Show Source):
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Probability-and-statistics/144614: A bag contains 5 apples and 3 oranges. If you select 4 pieces of fruit without looking, how many ways can you get exactly 3 apples?
A) 60 ways B) 180 ways
C) 20 ways D) 30 ways
can you please explain! 1 solutions
Answer 105371 by shahid(44) on 2008-06-08 15:38:26 (Show Source):
You can put this solution on YOUR website!we can get exactly three apples in  ways but since we have to select four pieces so one orange can be selected in  ways now by product rule
total ways to select four pieces =  *
=  * 
=  * 
=12*3
=36
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