Bob has 20 dollars. Bill has y dollars.
They decided to go to the movies. They only paid for their own tickets. Bob spent 2/5 of his money and Bill spent 4/15 of his money.
If the tickets were the same amount of money, how much money does Bill have?
First, you have to find how much each ticket costs. Bob has 20 dollars, and he spends 2/5 of it on the movie ticket. To find this, you can simply do 20*(2/5). You can also see that 1/5 of 20 dollars is 4 because 20/5=4. He used 2/5 which is double of 1/5 which means the ticket is 2*4=8. Using both methods, your answer will be, the movie ticket is 8 dollars.
Since the problem says that the tickets were the same amount of money, you can make the equation: 8=y*(4/15). The 8 stands for the price of the movie ticket, the y stands for how much money Bill has, and the 4/15 stands for the fraction of Bill's money spent on the movie ticket. As shown above, y*(4/15) will tell you how much 4/15 of y is.
Solving for y, you get 30. In conclusion, Bill has 30 dollars.
This is my FIRST every response to a question so hopefully this helps :)
(I do all my calculations on paper so you should probably solve the equations yourself to make sure I didn't make any silly mistakes.)