Some stickers are packed into exactly packets of 5.
If the stickers are repacked into packets of 20,
there are 3 less packets.
- How many packets are there?
- How many stickers are there?
|
Packets of 5 |
Packets of 20 |
Number |
1 u |
1 u - 3 |
Value |
5 |
20 |
Total value |
5 u |
20(1 u - 3) = 20 u - 60 |
(a)
Let the number of packets of 5 be 1 u.
Number of stickers in packets of 5
= 1 u x 5
= 5 u
Number of stickers in packets of 20
= 20 x (1 u - 3)
= 20 u - 60
5 u = 20 u - 60
20 u - 5 u = 60
15 u = 60
1 u = 60 ÷ 15 = 4
Number of packets of 5 = 4
(b)
Number of stickers
= 5 u
= 5 x 4
= 20
Answer(s): (a) 4; (b) 20