Justin had
38 as many marbles as Marion. After Justin bought another 13 marbles, he had 17 less marbles than Marion. How many marbles did Justin have at first?
|
Justin |
Marion |
Before |
3 u |
8 u |
Change |
+ 13 |
|
After |
3 u + 13 |
8 u |
Marion had 17 more marbles than Justin in the end. So, if Justin had another 17 marbles, he would have the same number of marbles as Marion.
8 u = 3 u + 13 + 17
8 u - 3 u = 13 + 17
5 u = 30
1 u = 30 ÷ 5 = 6
Number of marbles that Justin had at first
= 3 u
= 3 x 6
= 18
Answer: 18