PSLEThere were a total of 156 tables and chairs in a school field. There were 3 times as many chairs as tables. After 25 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 school field?
|
Tables |
Chairs |
Total |
Before |
1 u |
3 u |
156 |
Change |
- ? |
- 25 |
|
After |
1 p |
4 p |
|
Number of tables and chairs at first
= 3 u + 1 u
= 156
4 u = 156
1 u = 156 ÷ 4 = 39
Number of chairs at first
= 3 u
= 3 x 39
= 117
Number of chairs left
= 117 - 25
= 92
4 p = 92
1 p = 92 ÷ 4 = 23
Number of tables thrown away from the school field
= 39 - 23
= 16
Answer(s): 16