13 days ago, Lynn had a total of 200 purple and gold pens. 25% of her pens were gold pens. Today, her grandfather gave her some more pens. As a result, her purple pens increased by 10%. Now, 50% of her pens are gold pens. How many gold pens did her grandfather give her?
| |
Gold pens |
Purple pens |
Total
pens |
| Before |
1 u |
3 u |
200 |
| Change |
+ 2.3 u |
+ 0.3 u |
|
| After |
3.3 u |
3.3 u |
|
Comparing the
purple pens and
gold pens in the end |
1 |
1 |
|
25% =
25100 =
14 Gold pens : Purple pens = 1 : 3
Increase in the number of purple pens
= 10% x 3 u
=
10100 x 3 u
= 0.3 u
50% =
50100 =
12 In the end
Gold pens : Purple pens = 1 : 1
Number of pens at first
= 3 u + 1 u
= 4 u
4 u = 200
1 u = 200 ÷ 4 = 50
Number of gold pens that Lynn received from her grandfather
= 3.3 u - 1 u
= 2.3 u
= 2.3 x 50
= 115
Answer(s): 115
