There were some grapefruits at a mart. In the morning,
14 of grapefruits were sold. In the afternoon, another 23 grapefruits were sold. The total number of grapefruits sold was 4 less than
47 of the number of grapefruits the mart had at first.
- How many grapefruits were there at first?
- What fraction of the grapefruits in the mart remained unsold in the afternoon?
|
Comparison 1 |
Comparison 2 |
Before |
4x7 = 28 u |
7x4 = 28 u |
Change 1 |
- 1x7 = - 7 u |
|
After 1 |
3x7 = 21 u |
Change 2 |
- 23 |
After 2 |
21 u - 23 |
4x4 - 4 = 16 u - 4 |
(a)
The number of grapefruits at first is repeated in both comparisons. Make the number of grapefruits at first. LCM of 4 and 7 is 28.
The number of grapefruits in the end is the same in both comparisons.
21 u - 23 = 16 u - 4
21 u - 16 u = 23 - 4
9 u = 27
1 u = 27 ÷ 9 = 3
Number of grapefruits at first
= 28 u
= 28 x 3
= 84
(b)
Number of grapefruits that remained unsold
= 12 u + 4
= 12 x 3 + 4
= 40
Fraction of grapefruits that remained unsold
=
4084=
1021Answer(s): (a) 84; (b)
1021