Eva baked 150 puffs. 40% of them were chocolate puffs. How many more chocolate puffs must Eva bake so that 90% of her puffs are chocolate puffs?
| |
Chocolate puffs |
Other puffs |
| Before |
40% |
60% |
| Change |
+ ? |
No change |
| After |
90 u |
10 u |
Number of chocolate puffs at first
= 40% x 150
=
40100 x 150
= 60
Percentage of other puffs
= 100% - 40%
= 60%
Number of other puffs
= 60% x 150
=
60100 x 150
= 90
Number of other puffs in the end
= 100 u - 90 u
= 10 u
The number of other puffs remains unchanged.
60% = 10 u
10 u = 90
1 u = 90 ÷ 10 = 9
Number of chocolate puffs in the end
= 90 u
= 90 x 9
= 810
Additional number of chocolate puffs that Eva must bake
= 810 - 60
= 750
Answer(s): 750
