PSLEThere were a total of 132 tables and chairs in a canteen. There were 3 times as many chairs as tables. After 19 chairs and some tables were thrown away, there were 5 times as many chairs as tables left. How many tables were thrown away from the canteen?
|
Tables |
Chairs |
Total |
Before |
1 u |
3 u |
132 |
Change |
- ? |
- 19 |
|
After |
1 p |
5 p |
|
Number of tables and chairs at first
= 3 u + 1 u
= 132
4 u = 132
1 u = 132 ÷ 4 = 33
Number of chairs at first
= 3 u
= 3 x 33
= 99
Number of chairs left
= 99 - 19
= 80
5 p = 80
1 p = 80 ÷ 5 = 16
Number of tables thrown away from the canteen
= 33 - 16
= 17
Answer(s): 17