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