Some stickers are packed into exactly packets of 20.
If the stickers are repacked into packets of 8,
there are 7 more packets and 4 stickers left.
- How many packets are there?
- How many stickers are there?
|
Packets of 20 |
Packets of 8 |
Number |
1 u |
1 u + 7 |
Value |
20 |
8 |
Total value |
20 u |
8(1 u + 7) + 4 = 8 u + 60 |
(a)
Let the number of packets of 20 be 1 u.
Number of stickers if they are in packets of 20
= 1 u x 20
= 20 u
Number of stickers if they are in packets of 8
= 8 x (1 u + 7) + 4
= 8 u + 56 + 4
= 8 u + 60
20 u = 8 u + 60
20 u - 8 u = 60
12 u = 60
1 u = 60 ÷ 12 = 5
Number of packets of 20
= 1 u
= 5
(b)
Number of stickers
= 20 u
= 20 x 5
= 100
Answer(s): (a) 5; (b) 100