SOLUTION: Hello my name is Wanda, I have been trying to solve this by using the substitution system. The question is: A class of Math A 30 students contains twice as many girls as boys.

Question 221560: Hello my name is Wanda, I have been trying to solve this by using the substitution system.
The question is: A class of Math A 30 students contains twice as many girls as boys. Last Friday, when two of the boys were absent and all the girls were there, the number of girls tripled the number of boys. How many boys and how many girls are in the class?
These are the two equations I came up with. But I just can't make it work.
2G = B
3G = B - 2
I'd appreciate your help.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
The question is:
A class of Math A30 students contains twice as many girls as boys. Last Friday,
Equation:
g = 2b
--------------------------------
when two of the boys were absent and all the girls were there, the number of girls tripled the number of boys.
Equation:
g = 3(b-2)

How many boys and how many girls are in the class?
Substitute for "g" and solve for "b":
2b = 3b-6
b = 6 (# of boys before 2 were absent)
---
Since g = 3(b-2), g = 3(6-2) = 12 (# of girls)
==================================================
Cheers,
Stan H.
----------------------------------------------

RELATED QUESTIONS
I am working with my school website on My Math Lab and this is a question asked. I need... (answered by checkley77,Earlsdon)

Hello, I have recently started learning about the systems of linear equations. I... (answered by Earlsdon)

Hello. Ok the problem that I am having with my homework is this. The question says to... (answered by checkley71)

Hello, my name is Rebecca Ghisoiu. I attend Western Govorners University, an online... (answered by Theo)

hello my name is Jade and I'm trying to get the root of 77 without using my... (answered by scott8148)

I'm in grade 10 math and have finished solving word problems using linear systems. We... (answered by ankor@dixie-net.com)

Hello! My name is John, My Algebra class is studying linear equations and I got a... (answered by Alan3354)

Hello. I was wondering if I could get some assistance on this proof for my geometry... (answered by jim_thompson5910)

I cannot figure this one out and I have been trying for a while now. I need help please.... (answered by Edwin McCravy)