Some stickers are packed into exactly packets of 9.
If the stickers are repacked into packets of 20,
there are 4 less packets and needs 6 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 - 4 |
Value |
9 |
20 |
Total value |
9 u |
20 u - 66 |
(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 - 6
= 14
Number of stickers if they are in packets of 20
= 20(1 u - 4) + 14
= 20 u - 80 + 14
= 20 u - 66
9 u = 20 u - 66
20 u - 9 u = 66
11 u = 66
1 u = 66 ÷ 11 = 6
Number of packets of 9
= 1 u
= 6
(b)
Number of stickers
= 9 u
= 9 x 6
= 54
Answer(s): (a) 6; (b) 54