On a shelf, there were 78 skirts and jackets. Sam spilt soy milk on the shelf and stained 50% of the jackets and 20% of the skirts. If 60 skirts and jackets were still clean, how many clean jackets were there?
| |
Skirts |
Jackets |
Total |
| Stained |
1 u |
1 p |
18 |
| Clean |
4 u |
1 p |
60 |
| Total |
5 u |
2 p |
78 |
50% =
50100 =
12 20% =
20100 =
15 Number of stained clothes
= 78 - 60
= 18
4 u + 1 p = 60
1 p = 60 - 4 u --- (1)
1 u + 1 p = 18
1 p = 18 - 1 u --- (2)
(2) - (1)
18 - 1 u = 60 - 4 u
4 u - 1 u = 60 - 18
3 u = 42
1 u = 42 ÷ 3 = 14
Number of clean jackets is the same as the number of stained jackets.
Number of clean jackets
= 18 - 1 u
= 18 - 14
= 4
Answer(s): 4
