7 days ago, Usha had a total of 300 white and purple stamps. 30% of her stamps were purple stamps. Today, her mother gave her some more stamps. As a result, her white stamps increased by 20%. Now, 50% of her stamps are purple stamps. How many purple stamps did her mother give her?
| |
Purple stamps |
White stamps |
Total
stamps |
| Before |
3 u |
7 u |
300 |
| Change |
+ 5.4 u |
+ 1.4 u |
|
| After |
8.4 u |
8.4 u |
|
Comparing the
white stamps and
purple stamps in the end |
1 |
1 |
|
30% =
30100 =
310 Purple stamps : White stamps = 3 : 7
Increase in the number of white stamps
= 20% x 7 u
=
20100 x 7 u
= 1.4 u
50% =
50100 =
12 In the end
Purple stamps : White stamps = 1 : 1
Number of stamps at first
= 7 u + 3 u
= 10 u
10 u = 300
1 u = 300 ÷ 10 = 30
Number of purple stamps that Usha received from her mother
= 8.4 u - 3 u
= 5.4 u
= 5.4 x 30
= 162
Answer(s): 162
