Olivia baked 80 wafers. 25% of them were chocolate wafers. How many more chocolate wafers must Olivia bake so that 85% of her wafers are chocolate wafers?
| |
Chocolate wafers |
Other wafers |
| Before |
25% |
75% |
| Change |
+ ? |
No change |
| After |
85 u |
15 u |
Number of chocolate wafers at first
= 25% x 80
=
25100 x 80
= 20
Percentage of other wafers
= 100% - 25%
= 75%
Number of other wafers
= 75% x 80
=
75100 x 80
= 60
Number of other wafers in the end
= 100 u - 85 u
= 15 u
The number of other wafers remains unchanged.
75% = 15 u
15 u = 60
1 u = 60 ÷ 15 = 4
Number of chocolate wafers in the end
= 85 u
= 85 x 4
= 340
Additional number of chocolate wafers that Olivia must bake
= 340 - 20
= 320
Answer(s): 320
