PSLEThere were a total of 124 tables and chairs in a canteen. There were 3 times as many chairs as tables. After 13 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 |
3 u |
124 |
Change |
- ? |
- 13 |
|
After |
1 p |
4 p |
|
Number of tables and chairs at first
= 3 u + 1 u
= 124
4 u = 124
1 u = 124 ÷ 4 = 31
Number of chairs at first
= 3 u
= 3 x 31
= 93
Number of chairs left
= 93 - 13
= 80
4 p = 80
1 p = 80 ÷ 4 = 20
Number of tables thrown away from the canteen
= 31 - 20
= 11
Answer(s): 11