A stationery kiosk sells staplers in packs of 3 and 4. At first, there were 3 times as many packs of 3 as packs of 4. After selling half of the packs of 3 and some packs of 4, Mr Ee packs 20 additional packs of 4. How many packs of 3 and 4 are sold if there are 6 times as many packs of 3 as packs of 4 and there is a total of 66 unsold staplers?
| |
Packs of 3 |
Packs of 4 |
Comparing the number
of packs at first |
3x4 =
12 u |
1x4 =
4 u |
| Before |
2x6 =
12 u |
|
| Change 1 |
- 1x6 =
- 6 u |
- ? |
| Change 2 |
|
+ 20 |
| After |
1x6 =
6 u |
|
Comparing the number
of packs in the end |
6 u |
1 u |
The number of packs of 3 in the end is repeated. Make the number of packs of 3 in the end the same. LCM of 1 and 6 is 6.
The number of packs of 3 at first is repeated. Make the number of packs of 3 at first the same. LCM of 12 and 3 is 12.
Number of staplers
left unsold |
Packs of 3
|
Packs of 4
|
Total
|
| Number |
6 u |
1 u |
|
| Value |
3 |
4 |
|
| Total value |
18 u |
4 u |
22 u |
Total number of staplers left unsold
= (6 u x 3) + (1 u x 4)
= 18 u + 4 u
= 22 u
22 u = 66
1 u = 66 ÷ 22 = 3
Number of packs of 3 and 4 sold
= 6 u + (4 u - 1 u) + 20
= 6 u + 3 u + 20
= 9 u + 20
= 9 x 3 + 20
= 27 + 20
= 47
Answer(s): 47
