The ratio of Evelyn's marbles to Jack's marbles at first was 2 : 5. After Evelyn gave Jack 81 marbles, the ratio of Evelyn's marbles to Jack's marbles is 1 : 4. What was the number of marbles they had altogether?
|
Evelyn |
Jack |
Total |
Before |
2x5 = 10 u |
5x5 = 25 u
|
7x5 = 35 u |
Change |
- 81 |
+ 81 |
|
After |
1x7 = 7 u |
4x7 = 28 u |
5x7 = 35 u |
Number of marbles that Evelyn gave Jack
= 10 u - 7 u
= 3 u
3 u = 81
1 u = 81 ÷ 3 = 27
Total number of marbles that they had
= 35 u
= 35 x 27
= 945
Answer(s): 945