10 days ago, Penelope had a total of 200 brown and blue pens. 25% of her pens were blue pens. Today, her older sister gave her some more pens. As a result, her brown pens increased by 40%. Now, 50% of her pens are blue pens. How many blue pens did her older sister give her?
| |
Blue pens |
Brown pens |
Total
pens |
| Before |
1 u |
3 u |
200 |
| Change |
+ 3.2 u |
+ 1.2 u |
|
| After |
4.2 u |
4.2 u |
|
Comparing the
brown pens and
blue pens in the end |
1 |
1 |
|
25% =
25100 =
14 Blue pens : Brown pens = 1 : 3
Increase in the number of brown pens
= 40% x 3 u
=
40100 x 3 u
= 1.2 u
50% =
50100 =
12 In the end
Blue pens : Brown pens = 1 : 1
Number of pens at first
= 3 u + 1 u
= 4 u
4 u = 200
1 u = 200 ÷ 4 = 50
Number of blue pens that Penelope received from her older sister
= 4.2 u - 1 u
= 3.2 u
= 3.2 x 50
= 160
Answer(s): 160
