Roshel baked 150 biscuits. 40% of them were chocolate biscuits. How many more chocolate biscuits must Roshel bake so that 70% of her biscuits are chocolate biscuits?
| |
Chocolate biscuits |
Other biscuits |
| Before |
40% |
60% |
| Change |
+ ? |
No change |
| After |
70 u |
30 u |
Number of chocolate biscuits at first
= 40% x 150
=
40100 x 150
= 60
Percentage of other biscuits
= 100% - 40%
= 60%
Number of other biscuits
= 60% x 150
=
60100 x 150
= 90
Number of other biscuits in the end
= 100 u - 70 u
= 30 u
The number of other biscuits remains unchanged.
60% = 30 u
30 u = 90
1 u = 90 ÷ 30 = 3
Number of chocolate biscuits in the end
= 70 u
= 70 x 3
= 210
Additional number of chocolate biscuits that Roshel must bake
= 210 - 60
= 150
Answer(s): 150
