11 days ago, Zara had a total of 160 green and brown stamps. 25% of her stamps were brown stamps. Today, her father gave her some more stamps. As a result, her green stamps increased by 30%. Now, 50% of her stamps are brown stamps. How many brown stamps did her father give her?
| |
Brown stamps |
Green stamps |
Total
stamps |
| Before |
1 u |
3 u |
160 |
| Change |
+ 2.9 u |
+ 0.9 u |
|
| After |
3.9 u |
3.9 u |
|
Comparing the
green stamps and
brown stamps in the end |
1 |
1 |
|
25% =
25100 =
14 Brown stamps : Green stamps = 1 : 3
Increase in the number of green stamps
= 30% x 3 u
=
30100 x 3 u
= 0.9 u
50% =
50100 =
12 In the end
Brown stamps : Green stamps = 1 : 1
Number of stamps at first
= 3 u + 1 u
= 4 u
4 u = 160
1 u = 160 ÷ 4 = 40
Number of brown stamps that Zara received from her father
= 3.9 u - 1 u
= 2.9 u
= 2.9 x 40
= 116
Answer(s): 116
