Some stickers are packed into exactly packets of 10.
If the stickers are repacked into packets of 7,
there are 6 more packets.
- How many packets of 7 are there?
- How many stickers are there?
|
Packets of 10 |
Packets of 7 |
Number |
1 u |
1 u + 6 |
Value |
10 |
7 |
Total value |
10 u |
7 u + 42 |
(a)
Let the number of packets of 10 be 1 u.
Number of stickers if they are in packets of 10
= 10 x 1 u
= 10 u
Number of stickers if they are in packets of 7
= 7 x (1 u + 6)
= 7 u + 42
7 u + 42 = 10 u
10 u - 7 u = 42
3 u = 42
1 u = 42 ÷ 3 = 14
Number of packets of 7
= 1 u + 6
= 14 + 6
= 20
(b)
Number of stickers
= 10 u
= 10 x 14
= 140
Answer(s): (a) 20; (b) 140