Some stickers are packed into exactly packets of 5.
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 5 |
Packets of 13 |
Number |
1 u |
1 u - 2 |
Value |
5 |
13 |
Total value |
5 u |
13 u - 16 |
(a)
Let the number of packets of 5 be 1 u.
Number of stickers if they are in packets of 5
= 1 u x 5
= 5 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
5 u = 13 u - 16
13 u - 5 u = 16
8 u = 16
1 u = 16 ÷ 8 = 2
Number of packets of 5
= 1 u
= 2
(b)
Number of stickers
= 5 u
= 5 x 2
= 10
Answer(s): (a) 2; (b) 10