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