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