Some stickers are packed into exactly packets of 7.
If the stickers are repacked into packets of 17,
there are 2 less packets and needs 3 more stickers to make another packet.
- How many packets are there?
- How many stickers are there?
|
Packets of 7 |
Packets of 17 |
Number |
1 u |
1 u - 2 |
Value |
7 |
17 |
Total value |
7 u |
17 u - 20 |
(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 left if another packet is not packed
= 17 - 3
= 14
Number of stickers if they are in packets of 17
= 17(1 u - 2) + 14
= 17 u - 34 + 14
= 17 u - 20
7 u = 17 u - 20
17 u - 7 u = 20
10 u = 20
1 u = 20 ÷ 10 = 2
Number of packets of 7
= 1 u
= 2
(b)
Number of stickers
= 7 u
= 7 x 2
= 14
Answer(s): (a) 2; (b) 14