Some stickers are packed into exactly packets of 9.
If the stickers are repacked into packets of 12,
there are 7 less packets.
- How many packets are there?
- How many stickers are there?
|
Packets of 9 |
Packets of 12 |
Number |
1 u |
1 u - 7 |
Value |
9 |
12 |
Total value |
9 u |
12(1 u - 7) = 12 u - 84 |
(a)
Let the number of packets of 9 be 1 u.
Number of stickers in packets of 9
= 1 u x 9
= 9 u
Number of stickers in packets of 12
= 12 x (1 u - 7)
= 12 u - 84
9 u = 12 u - 84
12 u - 9 u = 84
3 u = 84
1 u = 84 ÷ 3 = 28
Number of packets of 9 = 28
(b)
Number of stickers
= 9 u
= 9 x 28
= 252
Answer(s): (a) 28; (b) 252