Ivory baked 20 muffins. 25% of them were chocolate muffins. How many more chocolate muffins must Ivory bake so that 85% of her muffins are chocolate muffins?
| |
Chocolate muffins |
Other muffins |
| Before |
25% |
75% |
| Change |
+ ? |
No change |
| After |
85 u |
15 u |
Number of chocolate muffins at first
= 25% x 20
=
25100 x 20
= 5
Percentage of other muffins
= 100% - 25%
= 75%
Number of other muffins
= 75% x 20
=
75100 x 20
= 15
Number of other muffins in the end
= 100 u - 85 u
= 15 u
The number of other muffins remains unchanged.
75% = 15 u
15 u = 15
1 u = 15 ÷ 15 = 1
Number of chocolate muffins in the end
= 85 u
= 85 x 1
= 85
Additional number of chocolate muffins that Ivory must bake
= 85 - 5
= 80
Answer(s): 80
