Some stickers are packed into exactly packets of 9.
If the stickers are repacked into packets of 13,
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 13 |
Number |
1 u |
1 u - 2 |
Value |
9 |
13 |
Total value |
9 u |
13 u - 16 |
(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
= 13 - 3
= 10
Number of stickers if they are in packets of 13
= 13(1 u - 2) + 10
= 13 u - 26 + 10
= 13 u - 16
9 u = 13 u - 16
13 u - 9 u = 16
4 u = 16
1 u = 16 ÷ 4 = 4
Number of packets of 9
= 1 u
= 4
(b)
Number of stickers
= 9 u
= 9 x 4
= 36
Answer(s): (a) 4; (b) 36