There were some pears at a shop. In the morning,
13 of pears were sold. In the afternoon, another 21 pears were sold. The total number of pears left was 5 less than
47 of the number of pears the shop had at first.
- How many pears were there at first?
- What fraction of the pears in the shop remained unsold in the afternoon?
| |
Comparison 1 |
Comparison 2 |
| Before |
3x7 =
21 u |
7x3 =
21 u |
| Change 1 |
- 1x7 =
- 7 u |
|
| After 1 |
2x7 =
14 u |
| Change 2 |
- 21 |
After 2 |
14 u - 21 |
4x3 - 5 =
12 u - 5 |
(a)
The number of pears at first is repeated in both comparisons. Make the number of pears at first. LCM of 3 and 7 is 21.
The number of pears in the end is the same in both comparisons.
14 u - 21 = 12 u - 5
14 u - 12 u = 21 - 5
2 u = 16
1 u = 16 ÷ 2 = 8
Number of pears at first
= 21 u
= 21 x 8
= 168
(b)
Number of pears that remained unsold
= 14 u - 21
= 14 x 8 - 21
= 112 - 21
= 91
Fraction of pears that remained unsold
=
91168=
1324Answer(s): (a) 168; (b)
1324 
