On a shelf, there were 101 cardigans and sweaters. Zane spilt hot soy milk on the shelf and stained 50% of the sweaters and 20% of the cardigans. If 79 cardigans and sweaters were still clean, how many stained sweaters were there?
| |
Cardigans |
Sweaters |
Total |
| Stained |
1 u |
1 p |
22 |
| Clean |
4 u |
1 p |
79 |
| Total |
5 u |
2 p |
101 |
50% =
50100 =
12 20% =
20100 =
15 Number of stained clothes
= 101 - 79
= 22
4 u + 1 p = 79
1 p = 79 - 4 u --- (1)
1 u + 1 p = 22
1 p = 22 - 1 u --- (2)
(2) - (1)
22 - 1 u = 79 - 4 u
4 u - 1 u = 79 - 22
3 u = 57
1 u = 57 ÷ 3 = 19
Number of stained sweaters
= 22 - 1 u
= 22 - 19
= 3
Answer(s): 3
