A stationery booth sells markers in packs of 5 and 8. At first, there were 4 times as many packs of 5 as packs of 8. After selling half of the packs of 5 and some packs of 8, Mr Ang packs 11 additional packs of 8. How many packs of 5 are sold if there are 8 times as many packs of 5 as packs of 8 and there is a total of 96 unsold markers?
| |
Packs of 5 |
Packs of 8 |
Comparing the number
of packs at first |
4x4 =
16 u |
1x4 =
4 u |
| Before |
2x8 =
16 u |
|
| Change 1 |
- 1x8 =
- 8 u |
- ? |
| Change 2 |
|
+ 11 |
| After |
1x8 =
8 u |
|
Comparing the number
of packs in the end |
8 u |
1 u |
The number of packs of 5 in the end is repeated. Make the number of packs of 5 in the end the same. LCM of 1 and 8 is 8.
The number of packs of 5 at first is repeated. Make the number of packs of 5 at first the same. LCM of 16 and 4 is 16.
Number of markers
left unsold |
Packs of 5
|
Packs of 8
|
Total
|
| Number |
8 u |
1 u |
|
| Value |
5 |
8 |
|
| Total value |
40 u |
8 u |
48 u |
Total number of markers left unsold
= (8 u x 5) + (1 u x 8)
= 40 u + 8 u
= 48 u
48 u = 96
1 u = 96 ÷ 48 = 2
Number of packs of 8 sold
= (4 u - 1 u) + 11
= 3 u + 11
= 3 x 2 + 11
= 6 + 11
= 17
Answer(s): 17
