Questions on Algebra: Average answered by real tutors!

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Question 258079: I have to solve this problem by substitution:
2x + y = 6
x= 3y + 10
I begin by using the 2(3y + 10)+ y = 6
Multiply: (6y + 20) + y = 6
add 6y + y to get 7y + 20= 6
-20= 6 -20
7y = -14
7ydivided by 7 = -14 divided by 7
y = -2
put the -2 for the y x = 3 (-2) + 10
x = -6 + 10
x = 4
so my answer would be
(4,-2)
My answer works out when I check my work. Please confirm that my work is correct.

Click here to see answer by Greenfinch(383)

Question 258316: The average (arithmetic mean) of a and b is 10, whereas the average of b and 10 is c/2. What is the average of a and c?
Click here to see answer by Theo(3458)

Question 258846: Hi, I'm trying to help my son with this problem. My answer was 23/30 is that correct?
Simplify: 2/3 +3/10 -2/5
2/3 + 3/10 = 11/30 then that minus 2/5? When I did it on an online math calculator, it said the answer is 17/30. I don't understand how that can be?
Thanks for your help! :)
Click here to see answer by Fombitz(13828)

Question 259031: what is the six number if five numbers are 90,95,85,95,and 75 and the average of all the numbers are 90 what is the six number
Click here to see answer by palanisamy(496)

Question 259298: I need to find the the number of tickets issued based on an average price.
I have yearly sales of $102,286
The average cost of each ticket is $340
What is the number of tickets sold?

Click here to see answer by richwmiller(9135)

Question 259215: Gina’s test results are 82, 87, 94, and 98. What is the lowest score she can
achieve on the fifth test and still maintain an average of 90?
(A) 82 (B) 89 (C) 90 (D) 94 (E) 95

Click here to see answer by Fombitz(13828)

Question 259537: Adam tried to compute the average of his 7 test scores. He mistakenly divided the
correct sum of all of his test scores by 6, which yielded 84. What is Adam’s correct
average test score?
Click here to see answer by ankor@dixie-net.com(15632)

Question 259731: if i received 8 referrals and that was 44% of the hospitals volume then what was their total number of referrals
Click here to see answer by drk(1908)

Question 259769: A student wrote 69 as the average of the data: 70, 59, 72, 35, 67, 78, 68, 81, 80, and 76. That answer was wrong by
Click here to see answer by CharlesG2(828)

Question 259908: How do you set this word problem up in algebra equation and solve for x?suzy invested part of her 12,000 bonus in fund that paid 10% pfofit and invested the rest in stock that suffered 3% loss find amt of each investment if her overall net profit was 550?
Click here to see answer by stanbon(57231)

Question 259964: The average of s and t is 12, and the average of s and t and u is 15. What is the value of u?

Click here to see answer by mananth(12270)

Question 260205: The average(arithmetic mean) of nine numbers is 9. When a tenth number is added the average of the ten numbers is also 9. What is the tenth number ?
a) 9/10 b) 10/9 c) 9 d) 10
Click here to see answer by edjones(7569)

Question 260539: Sarah has gotten scores of 83, 76, and 69 on her first three tests. What score must she get on her fourth test to keep an average of 81 or greater.
fourth test = x
x = (83 + 76 + 69)/3
x = 76
Is this correct?
Click here to see answer by drk(1908)

Question 260879: if i have 67% in math and the final exam is worth 30%, what grade do i need in the final exam to get a 50 in the whole subject?
Click here to see answer by drk(1908)

Question 261043: A student scores 86, 78, 91, 94, and 83 on five exams where 100 is perfect. The final exam counts as much as two regular exams. What score does the student have to make on the final to have a 90% average for the course?
Click here to see answer by ankor@dixie-net.com(15632)

Question 261130: Marks: 1 Given the equation 4x + 7y = 21, Find y when x = 14.
Click here to see answer by unlockmath(1599)

Question 261568: how to figure how many questions you got wrong on a test if there are 225 questions and a total of 500 points and i got a 462
Click here to see answer by stanbon(57231)

Question 261568: how to figure how many questions you got wrong on a test if there are 225 questions and a total of 500 points and i got a 462
Click here to see answer by richwmiller(9135)

Question 261743: you currently have had three test grades with a result of 91, 86, and 89. there is one test left and you want to know what is the lowest grade you can get on this test to have an a average (90%) in the class.How would you translate and solve this problem?
Click here to see answer by richwmiller(9135)

Question 261605: Suppose your grades on your first four exams were 84%, 90%, 68%, and 89%. What would be the lowest possible average that your last two exams could have so that your grade in the class, based on the average of the six exams, is at least 78%?
Click here to see answer by checkley77(12569)

Question 262267: You have an average of 83 after 5 tests. How do you determine what the score is of each test to get the average of 83?
Click here to see answer by richwmiller(9135)

Question 262228: In june a baseball team that played 60 games had won 30% of its game played. After a phenomenal winning streak this team raised its average to 50% .How many games must the team have won in a row to attain this average?

A. 12 B. 20 C. 24 D. 30

Click here to see answer by ankor@dixie-net.com(15632)

Question 262639: If one third of my grade consists of homework and I receive 90 for that and two thirds of my grade consists of tests and I receive a 84.83, what is my grade?
Click here to see answer by richwmiller(9135)

Question 263062: hi, i have got to find two numbers whose sum is 108 and whose difference is 54 thanks
Click here to see answer by nerdybill(6948)

Question 263805: Janice has an average of 74 on the first three tests in her algebra class. On the final four tests, she scored 92, 90, 94, and 76. What was her average for the entire year?
Click here to see answer by mananth(12270)

Question 264239: 1562 miles is equal how many hours?
Click here to see answer by Alan3354(30982)

Question 264335: (3w-6)2/3
Click here to see answer by JBarnum(2044)

Question 265238: If a student had taken six tests and recieved scores of 88, 73,81,83,79 and 94 what would the 7th test score have to be to have a mean score of 83?
Click here to see answer by dabanfield(803)

Question 265256: my test grades are 86,83,80,65,72,88,81,96 what is my overall average
Click here to see answer by drk(1908)

Question 1822: shawn needs to have a 90% average for his exam grade to make an A for the quarter there are three tests in the quarter and his first two exams percentage were 91%,87% what score must he get on the third exam to obtain a 90% average?
90 x 3 = 270
270-87 - 91 = 92
Click here to see answer by ahmad.rakhaa(1)

Question 266410: Fifteen people took part in a free-throw competition. The first participant scored
x points, the second scored y points, the third scored the arithmetic mean of the
number of points scored by the first two, and each subsequent competitor scored
the arithmetic mean of the number of points scored by all previous ones. How
many points did the last competitor score?

(A) (x+y)/2 (B) 12(x+y)/14 (C) 13(x+y)/15
(D) 14(x+y)/16 (E) none of these

Click here to see answer by user_dude2008(1861)

Question 266441: 2x-5x-7

Click here to see answer by jim_thompson5910(28503)

Question 266540: The average age of three members of a quartet is 57 years.What is the age of the fourth member, in years, if the quartet’s overall average age is 62 years.
Click here to see answer by drk(1908)

Question 266775: Write 5 different numbers that together have an average of -12.
Click here to see answer by drk(1908)

Question 267102: A survey of 82 high school students revealed that 42 like folk music, 20 like classical music, and 8 like both. How many of the students surveyed do not like either folk or classical music?
Click here to see answer by richwmiller(9135)

Question 267101: Of the 137 students who took a mathematics exam, 94 correctly answered the first question, 69 correctly answered the second question, and 54 correctly answered both questions. How many students did not answer either of the two questions correctly?
Click here to see answer by solver91311(16868)

Question 267059: A student has scores of 83, 89, 78, and 86 on her first four tests. what score must she get on her fifth exam so that the average for all 5 exams is 85 or higher?
Click here to see answer by scott8148(6628)

Question 268087: Solve for x, in interval notation: x^2-3/x-3 > or = 1/x-3. I came up with [-2,2]U[3,infinity). The quiz said it should be [-2,2]U(3,infinity). I think the book is wrong. If not, why wouldn't 3 be the = part?
Click here to see answer by jim_thompson5910(28503)

Question 269002: How would you work out this problem; It requires to show all work!
The cafeteria has 360 roses to sell for Valentine's Day. You want to pick
out a perfect red rose for someone special. When you get to the cafeteria
you discover:
*every third rose is too short
*every fourth rose has too many thorns
*every fifth rose is wilted
*every sixth rose is pink
*every eighth rose is yellow
If these are the only problems that the roses have, how many perfect roses are
there for you to choose from?
The problem requires to show all work. I would think that there is an
algebraic expression that would help me out, but I am in need of help.
I can help myself by making pictures to help visualize, but I think there must
be a better way.
Please help me if you can. Thank you!
Click here to see answer by josmiceli(9654)

Question 268213: what is the answer to 5x+2(11-4)=82+x?
Click here to see answer by cornball3440(16)

Question 270743: You have scored 75,79,78,and 78 in four test out of five tests. You want to score an overall b grade (80). You have the fifth test to pull up your score. How much minimum should you score in the fifth test so that you raise your average to 80(get an overall B grade).
Click here to see answer by stanbon(57231)

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