Some stickers are packed into exactly packets of 9.
If the stickers are repacked into packets of 15,
there are 5 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 15 |
Number |
1 u |
1 u - 5 |
Value |
9 |
15 |
Total value |
9 u |
15 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
= 15 - 6
= 9
Number of stickers if they are in packets of 15
= 15(1 u - 5) + 9
= 15 u - 75 + 9
= 15 u - 66
9 u = 15 u - 66
15 u - 9 u = 66
6 u = 66
1 u = 66 ÷ 6 = 11
Number of packets of 9
= 1 u
= 11
(b)
Number of stickers
= 9 u
= 9 x 11
= 99
Answer(s): (a) 11; (b) 99