PSLEThere were a total of 141 tables and chairs in a canteen. There were 2 times as many chairs as tables. After 22 chairs and some tables were thrown away, there were 4 times as many chairs as tables left. How many tables were thrown away from the canteen?
|
Tables |
Chairs |
Total |
Before |
1 u |
2 u |
141 |
Change |
- ? |
- 22 |
|
After |
1 p |
4 p |
|
Number of tables and chairs at first
= 2 u + 1 u
= 141
3 u = 141
1 u = 141 ÷ 3 = 47
Number of chairs at first
= 2 u
= 2 x 47
= 94
Number of chairs left
= 94 - 22
= 72
4 p = 72
1 p = 72 ÷ 4 = 18
Number of tables thrown away from the canteen
= 47 - 18
= 29
Answer(s): 29