Some stickers are packed into exactly packets of 9.
If the stickers are repacked into packets of 12,
there are 2 less packets and needs 3 more stickers to make another packet.
- How many packets are there?
- How many stickers are there?
|
Packets of 9 |
Packets of 12 |
Number |
1 u |
1 u - 2 |
Value |
9 |
12 |
Total value |
9 u |
12 u - 15 |
(a)
Let the number of packets of 9 be 1 u.
Number of stickers if they are in packets of 9
= 1 u x 9
= 9 u
Number of stickers left if another packet is not packed
= 12 - 3
= 9
Number of stickers if they are in packets of 12
= 12(1 u - 2) + 9
= 12 u - 24 + 9
= 12 u - 15
9 u = 12 u - 15
12 u - 9 u = 15
3 u = 15
1 u = 15 ÷ 3 = 5
Number of packets of 9
= 1 u
= 5
(b)
Number of stickers
= 9 u
= 9 x 5
= 45
Answer(s): (a) 5; (b) 45