Eric had
79 as many marbles as Emily. After Eric bought another 18 marbles, he had 20 less marbles than Emily. How many marbles did Eric have at first?
|
Eric |
Emily |
Before |
7 u |
9 u |
Change |
+ 18 |
|
After |
7 u + 18 |
9 u |
Emily had 20 more marbles than Eric in the end. So, if Eric had another 20 marbles, he would have the same number of marbles as Emily.
9 u = 7 u + 18 + 20
9 u - 7 u = 18 + 20
2 u = 38
1 u = 38 ÷ 2 = 19
Number of marbles that Eric had at first
= 7 u
= 7 x 19
= 133
Answer: 133