8 days ago, Roshel had a total of 275 silver and brown pens. 20% of her pens were brown pens. Today, her grandmother gave her some more pens. As a result, her silver pens increased by 10%. Now, 50% of her pens are brown pens. How many brown pens did her grandmother give her?
| |
Brown pens |
Silver pens |
Total
pens |
| Before |
1 u |
4 u |
275 |
| Change |
+ 3.4 u |
+ 0.4 u |
|
| After |
4.4 u |
4.4 u |
|
Comparing the
silver pens and
brown pens in the end |
1 |
1 |
|
20% =
20100 =
15 Brown pens : Silver pens = 1 : 4
Increase in the number of silver pens
= 10% x 4 u
=
10100 x 4 u
= 0.4 u
50% =
50100 =
12 In the end
Brown pens : Silver pens = 1 : 1
Number of pens at first
= 4 u + 1 u
= 5 u
5 u = 275
1 u = 275 ÷ 5 = 55
Number of brown pens that Roshel received from her grandmother
= 4.4 u - 1 u
= 3.4 u
= 3.4 x 55
= 187
Answer(s): 187
