PSLEThere were a total of 188 tables and chairs in a canteen. There were 3 times as many chairs as tables. After 21 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 |
188 |
Change |
- ? |
- 21 |
|
After |
1 p |
5 p |
|
Number of tables and chairs at first
= 3 u + 1 u
= 188
4 u = 188
1 u = 188 ÷ 4 = 47
Number of chairs at first
= 3 u
= 3 x 47
= 141
Number of chairs left
= 141 - 21
= 120
5 p = 120
1 p = 120 ÷ 5 = 24
Number of tables thrown away from the canteen
= 47 - 24
= 23
Answer(s): 23