Hazel gave 10% of her collection of coins to Sarah thereby increasing Sarah's collection by 20%. If Hazel had 45 coins left, how many coins did Sarah have at first?
| |
Hazel's coins |
Sarah's coins |
| Before |
100% |
100 u |
| Change |
- 10% |
+ 10% = + 20 u |
| After |
90% |
120 u |
90% of Hazel's collection = 45
1% of Hazel's collection = 45 ÷ 90 = 0.5
10% of Hazel's collection = 10 x 0.5 = 5
20 u of Sarah's collection = 5
1 u of Sarah's collection =
525 = 0.25
100 u of Sarah's collection = 100 x 0.25 = 25
Answer(s): 25
