2/5 of Elvis's money was 6/7 of Noah's money. After Noah received $20 from his mother and Elvis spent $36 on a bag, both of them had an equal amount of money left. How much did Elvis have in the end?
Lets say E is Elvis's money and N is Noah's Money
Start by making an equation:
And make a second equation:
N+20 = E - 36
N + 56= E
You can derive this from the second sentence.
Then plug in N+56=E into the first equation:
Multiply by 35 on both sides to cancel the denominators
14(N+56) = 30 N
14 N + 14 • 56 = 30 N
14 • 56 = 16 N
Divide both sides by power of 2 till N is isolated so the calculation isn't so messy.
14 • 7 = 2 N
7 • 7 = N
49 = N
Reread the question now to see what the question was about:
We need to find elvis's money at the end
That is equal to 49+20 = 69
So the answer is $69