Some stickers are packed into exactly packets of 10.
If the stickers are repacked into packets of 7,
there are 5 more packets and 4 stickers left.
- How many packets are there?
- How many stickers are there?
|
Packets of 10 |
Packets of 7 |
Number |
1 u |
1 u + 5 |
Value |
10 |
7 |
Total value |
10 u |
7(1 u + 5) + 4 = 7 u + 39 |
(a)
Let the number of packets of 10 be 1 u.
Number of stickers if they are in packets of 10
= 1 u x 10
= 10 u
Number of stickers if they are in packets of 7
= 7 x (1 u + 5) + 4
= 7 u + 35 + 4
= 7 u + 39
10 u = 7 u + 39
10 u - 7 u = 39
3 u = 39
1 u = 39 ÷ 3 = 13
Number of packets of 10
= 1 u
= 13
(b)
Number of stickers
= 10 u
= 10 x 13
= 130
Answer(s): (a) 13; (b) 130