A basket contained yellow and black stamps. There were 60% more yellow stamps than black stamps. When 13 more stamps were poured into the basket, the amount of yellow stamps increased by 25% and the amount of black stamps increased 90%. How many stamps were in the basket at first?
| |
Yellow stamps |
Black stamps |
Total stamps |
| Before |
8 u |
5 u |
13 u |
| Change |
+ 2 u |
+ 4.5 u |
+ 6.5 u |
| After |
10 u |
9.5 u |
19.5 u |
100% + 60% = 160%
160% =
160100 =
85Number of more yellow stamps that were poured into the basket
= 25% x 8 u
=
25100 x 8 u
= 2 u
Number of more black stamps that were poured into the basket
= 90% x 5 u
=
90100 x 5 u
= 4.5 u
Total number of more stamps that were poured into the basket
= 2 u + 4.5 u
= 6.5 u
6.5 u = 13
1 u = 13 ÷ 6.5 = 2
Number of stamps in the basket at first
= 8 u + 5 u
= 13 u
= 13 x 2
= 26
Answer(s): 26
