Some stickers are packed into exactly packets of 9.
If the stickers are repacked into packets of 20,
there are 3 less packets and needs 4 more stickers to make another packet.
- How many packets are there?
- How many stickers are there?
|
Packets of 9 |
Packets of 20 |
Number |
1 u |
1 u - 3 |
Value |
9 |
20 |
Total value |
9 u |
20 u - 44 |
(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
= 20 - 4
= 16
Number of stickers if they are in packets of 20
= 20(1 u - 3) + 16
= 20 u - 60 + 16
= 20 u - 44
9 u = 20 u - 44
20 u - 9 u = 44
11 u = 44
1 u = 44 ÷ 11 = 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