Fanny gave 10% of her collection of erasers to Dana thereby increasing Dana's collection by 20%. If Fanny had 36 erasers left, how many erasers did Dana have at first?
| |
Fanny's erasers |
Dana's erasers |
| Before |
100% |
100 u |
| Change |
- 10% |
+ 10% = + 20 u |
| After |
90% |
120 u |
90% of Fanny's collection = 36
1% of Fanny's collection = 36 ÷ 90 = 0.4
10% of Fanny's collection = 10 x 0.4 = 4
20 u of Dana's collection = 4
1 u of Dana's collection =
420 = 0.2
100 u of Dana's collection = 100 x 0.2 = 20
Answer(s): 20
