On a shelf, there were 99 jackets and cardigans. Ivan spilt milk on the shelf and stained 50% of the cardigans and 20% of the jackets. If 75 jackets and cardigans were still clean, how many clean cardigans were there?
| |
Jackets |
Cardigans |
Total |
| Stained |
1 u |
1 p |
24 |
| Clean |
4 u |
1 p |
75 |
| Total |
5 u |
2 p |
99 |
50% =
50100 =
12 20% =
20100 =
15 Number of stained clothes
= 99 - 75
= 24
4 u + 1 p = 75
1 p = 75 - 4 u --- (1)
1 u + 1 p = 24
1 p = 24 - 1 u --- (2)
(2) - (1)
24 - 1 u = 75 - 4 u
4 u - 1 u = 75 - 24
3 u = 51
1 u = 51 ÷ 3 = 17
Number of clean cardigans is the same as the number of stained cardigans.
Number of clean cardigans
= 24 - 1 u
= 24 - 17
= 7
Answer(s): 7
