The ratio of William's stamps to Emily's stamps at first was 3 : 7. After William gave Emily 85 stamps, the ratio of William's stamps to Emily's stamps is 1 : 4. What was the number of stamps they had altogether?
|
William |
Emily |
Total |
Before |
3x5 = 15 u |
7x5 = 35 u
|
10x5 = 50 u |
Change |
- 85 |
+ 85 |
|
After |
1x10 = 10 u |
4x10 = 40 u |
5x10 = 50 u |
Number of stamps that William gave Emily
= 15 u - 10 u
= 5 u
5 u = 85
1 u = 85 ÷ 5 = 17
Total number of stamps that they had
= 50 u
= 50 x 17
= 850
Answer(s): 850