The ratio of Ben's money to John's money was 9:4. After Ben spent $63 on books, the ratio became 1:2. How much more money did John have than Ben then?
Initially Ben had 9x dollars and John has 4x dollars.
Ben spends $63 so now Ben has 9x-63 dollars and John still has 4x dolllars.
This is in the ration 1:2
so
\(\frac{9x-63}{1}=\frac{4x}{2}\\ 9x-63=2x\\ 7x=63\\ x=9\)
You can finish it :)
Let Ben's money = 2x
and John's money = y
Therefore x:y = 9:4
i.e x/y = 9/4 Cross multiply
4x = 9y -- (1)
After Ben spends $63
Ben's money becomes x - 63
x - 63 : y = 1:2
(x - 63)/y = 1/2
2(x - 63) = y
2x - 126 = y
Input value of y in eq (1)
4x = 9(2x - 126)
4x = 18x - 1134
1134 = 18x - 4x
1134 = 14x
1134/14 = x x = 89
Since 4x = 9y
4 (81) = 9y
324 = 9y
324/9 = y
36 = y
Ben's money = $81 and
John's money = $36
After Ben spends $63 his money
becomes $81 - $63 = $18
John becomes $(36 - 18) more = $18 more