PSLEThere were a total of 120 tables and chairs in a school field. There were 3 times as many chairs as tables. After 14 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 |
120 |
Change |
- ? |
- 14 |
|
After |
1 p |
4 p |
|
Number of tables and chairs at first
= 3 u + 1 u
= 120
4 u = 120
1 u = 120 ÷ 4 = 30
Number of chairs at first
= 3 u
= 3 x 30
= 90
Number of chairs left
= 90 - 14
= 76
4 p = 76
1 p = 76 ÷ 4 = 19
Number of tables thrown away from the school field
= 30 - 19
= 11
Answer(s): 11