On a shelf, there were 60 skirts and cardigans. Jeremy spilt hot coffee on the shelf and stained 50% of the cardigans and 20% of the skirts. If 39 skirts and cardigans were still clean, how many stained cardigans were there?
| |
Skirts |
Cardigans |
Total |
| Stained |
1 u |
1 p |
21 |
| Clean |
4 u |
1 p |
39 |
| Total |
5 u |
2 p |
60 |
50% =
50100 =
12 20% =
20100 =
15 Number of stained clothes
= 60 - 39
= 21
4 u + 1 p = 39
1 p = 39 - 4 u --- (1)
1 u + 1 p = 21
1 p = 21 - 1 u --- (2)
(2) - (1)
21 - 1 u = 39 - 4 u
4 u - 1 u = 39 - 21
3 u = 18
1 u = 18 ÷ 3 = 6
Number of stained cardigans
= 21 - 1 u
= 21 - 6
= 15
Answer(s): 15
