Emma baked 60 biscuits. 25% of them were butter biscuits. How many more butter biscuits must Emma bake so that 85% of her biscuits are butter biscuits?
| |
Butter biscuits |
Other biscuits |
| Before |
25% |
75% |
| Change |
+ ? |
No change |
| After |
85 u |
15 u |
Number of butter biscuits at first
= 25% x 60
=
25100 x 60
= 15
Percentage of other biscuits
= 100% - 25%
= 75%
Number of other biscuits
= 75% x 60
=
75100 x 60
= 45
Number of other biscuits in the end
= 100 u - 85 u
= 15 u
The number of other biscuits remains unchanged.
75% = 15 u
15 u = 45
1 u = 45 ÷ 15 = 3
Number of butter biscuits in the end
= 85 u
= 85 x 3
= 255
Additional number of butter biscuits that Emma must bake
= 255 - 15
= 240
Answer(s): 240
