PSLEThere were a total of 140 tables and chairs in a parade square. 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 parade square?
|
Tables |
Chairs |
Total |
Before |
1 u |
3 u |
140 |
Change |
- ? |
- 13 |
|
After |
1 p |
4 p |
|
Number of tables and chairs at first
= 3 u + 1 u
= 140
4 u = 140
1 u = 140 ÷ 4 = 35
Number of chairs at first
= 3 u
= 3 x 35
= 105
Number of chairs left
= 105 - 13
= 92
4 p = 92
1 p = 92 ÷ 4 = 23
Number of tables thrown away from the parade square
= 35 - 23
= 12
Answer(s): 12