There was an equal number of chairs and desks in the morning. At 3 p.m., some chairs were added and some desks were removed, resulting in the number of chairs being increased by 20% while the number of desks decreased by 40%. At 8 p.m. the number of chairs increased by 50%. If a total of 48 chairs were added during the day, how many more chairs than desks were there in the end?
At 3 p.m. |
Chairs |
Desks |
Before |
1 u |
1 u |
Change |
+ 0.2 u |
- 0.4 u |
After |
1.2 u |
0.6 u |
At 8 p.m. |
Chairs |
Desks |
Before |
1.2 u |
0.6 u |
Change |
+ 0.6 u |
No change |
After |
1.8 u |
0.6 u |
Number of chairs added
= 20% x 1 u
=
20100 x 1 u
= 0.2 u
Number of desks removed
= 40% x 1 u
=
40100 x 1 u
= 0.4 u
Number of chairs increased by chairs at 8 p.m.
= 50% x 1.2 u
=
50100 x 1.2 u
= 0.6 u
Number of chairs added during the day
= 1.8 u - 1 u
= 0.8 u
0.8 u = 48
1 u = 48 ÷ 0.8 = 60
Number of more chairs than desks in the end
= 1.8 u - 0.6 u
= 1.2 u
= 1.2 x 60
= 72
Answer(s): 72