SOLUTION: Greetings everyone I have this following math word problem, Noah's class held a food drive for the holidays.There are a total of 25 students in his class.On average, each boy an

Question 1116013: Greetings everyone I have this following math word problem,
Noah's class held a food drive for the holidays.There are a total of 25 students in his class.On average, each boy and each girl brought in 3 cans of food.If the class brought in a total of 75 cans of food, how many girls are in class?
Thanks for any help in advance.(�▽｀)=b
Answer by Theo(13342) (Show Source): You can put this solution on YOUR website!
there were 25 students in the class.
each boy brought in 3 cans of food.
each girl brought in 3 cans of food.

the total number of cans of food that were brought is 75.

there is no way of telling how many boys or girls are in the class.

let x = number of boys.
let y = nmber of girls.

x + y = 25
3x + 3y = 75

these equations need to be solved simultaneously.

multiply both sides of the first equation by 3 and subtract the first eauation from the second.

you get 0 + 0 = 0

since both variables dropped out of the equation, then x or y can be any number that's valid.

the number of girls will be equal to the total minus the number of boys.

the number of girls can be anything between 0 and 25.

if the number of girls is 0, the number of boys is 25.
if the number of girls is 25, the number of boys is 0.

x can be anything between 0 and 25.

once you pick x, y will be 25 - x.

you will need tomething more to solve these equation.

something like each boy brought an average of 3 cans and each girl brought an average of 6 cans for a total of 105 cans.

your 2 equation then becomes:

x + y = 25
3x + 6y = 105

multiply both sides of the first equation by 3 to get:

3x + 3y = 75
3x + 6y = 105

subtract first equation from second toget 3y = 30
solve for y to get y = 10

since y = 10, x must be 15 because 25 - 10 = 15

you have x = 15 and y = 10
3x + 10y = 45 + 60 = 105.
x + y = 25

now the equation could be solved with the number of boys = 15 and the number of girls = 10.

as you originally expressed it, there is no one solution that works.

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