Some stickers are packed into exactly packets of 7.
If the stickers are repacked into packets of 12,
there are 4 less packets and 3 stickers extra.
- How many packets are there?
- How many stickers are there?
|
Packets of 7 |
Packets of 12 |
Number |
1 u |
1 u - 4 |
Value |
7 |
12 |
Total value |
7 u |
12 u - 45 |
(a)
Let the number of packets of 7 be 1 u.
Number of stickers if they are in packets of 7
= 1 u x 7
= 7 u
Number of stickers if they are in packets of 12
= 12(1 u - 4) + 3
= 12 u - 48 + 3
= 12 u - 45
7 u = 12 u - 45
12 u - 7 u = 45
5 u = 45
1 u = 45 ÷ 5 = 9
Number of packets of 7
= 1 u
= 9
(b)
Number of stickers
= 7 u
= 7 x 9
= 63
Answer(s): (a) 9; (b) 63