PSLEThere were a total of 165 tables and chairs in a canteen. There were 2 times as many chairs as tables. After 30 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 |
165 |
Change |
- ? |
- 30 |
|
After |
1 p |
4 p |
|
Number of tables and chairs at first
= 2 u + 1 u
= 165
3 u = 165
1 u = 165 ÷ 3 = 55
Number of chairs at first
= 2 u
= 2 x 55
= 110
Number of chairs left
= 110 - 30
= 80
4 p = 80
1 p = 80 ÷ 4 = 20
Number of tables thrown away from the canteen
= 55 - 20
= 35
Answer(s): 35