Julie baked 40 cupcakes. 25% of them were butter cupcakes. How many more butter cupcakes must Julie bake so that 70% of her cupcakes are butter cupcakes?
| |
Butter cupcakes |
Other cupcakes |
| Before |
25% |
75% |
| Change |
+ ? |
No change |
| After |
70 u |
30 u |
Number of butter cupcakes at first
= 25% x 40
=
25100 x 40
= 10
Percentage of other cupcakes
= 100% - 25%
= 75%
Number of other cupcakes
= 75% x 40
=
75100 x 40
= 30
Number of other cupcakes in the end
= 100 u - 70 u
= 30 u
The number of other cupcakes remains unchanged.
75% = 30 u
30 u = 30
1 u = 30 ÷ 30 = 1
Number of butter cupcakes in the end
= 70 u
= 70 x 1
= 70
Additional number of butter cupcakes that Julie must bake
= 70 - 10
= 60
Answer(s): 60
