SOLUTION: Having troubles with these word problems, 1. If the sides of a square are lenghtend by 5cm, the area becomes 121cm. What is the lenght? 2. If a pro basketball player has a ve

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Question 197313: Having troubles with these word problems,
1. If the sides of a square are lenghtend by 5cm, the area becomes 121cm. What is the lenght?
2. If a pro basketball player has a vertical leap of about 30 inches, what is his hang time? formula is V = 48T^2
3. Jack mows the lawn in 5 hours, Marilyn in 7 hours. How much time will it take if they mow lawn together?
Thank you in advance for your help...
Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website!
1. If the sides of a square are lengthened by 5cm, the area becomes 121cm.
What is the length?
Let (x+5) = the lengthened side
then
(x+5)^2 = 121 sq/cm
:
FOIL (x+5)(x+5)
x^2 + 10x + 25 = 121
:
x^2 + 10x + 25 - 121 = 0
:
x^2 + 10x - 96 = 0
Factor this
(x+16)(x-6) = 0
The positive solution is what we want here:
x = 6 is the length of the original square
and
6 + 5 = 11 = length of the larger square, 11^2 = 121 proves our solution
:
:
2. If a pro basketball player has a vertical leap of about 30 inches,
what is his hang time? formula is V = 48T^2
:
Replace V with 30 and solve for t
48T^2 = 30
T^2 =
T^2 =
T =
T = .79 ~ seconds
:
:
3. Jack mows the lawn in 5 hours, Marilyn in 7 hours.
How much time will it take if they mow lawn together?
:
Let = time required if they work together
Let the completed job = 1
;
A shared work equation:
+ = 1
:
Multiply equation by 35
7t + 5t = 35
:
12t = 35
:
t =
t = 2.9 hrs or 2 hrs + .9*60 = 54 min
;
;
Check solution on calc
enter: (2.9/7) + (2.9/5) = .99 ~ 1, confirms our solution