There were some grapefruits at a mart. In the morning,
16 of grapefruits were sold. In the afternoon, another 28 grapefruits were sold. The total number of grapefruits sold was 2 less than
512 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 |
6x2 = 12 u |
12x1 = 12 u |
Change 1 |
- 1x2 = - 2 u |
|
After 1 |
5x2 = 10 u |
Change 2 |
- 28 |
After 2 |
10 u - 28 |
5x1 - 2 = 5 u - 2 |
(a)
The number of grapefruits at first is repeated in both comparisons. Make the number of grapefruits at first. LCM of 6 and 12 is 12.
The number of grapefruits in the end is the same in both comparisons.
10 u - 28 = 5 u - 2
10 u - 5 u = 28 - 2
3 u = 30
1 u = 30 ÷ 3 = 10
Number of grapefruits at first
= 12 u
= 12 x 10
= 120
(b)
Number of grapefruits that remained unsold
= 7 u + 2
= 7 x 10 + 2
= 72
Fraction of grapefruits that remained unsold
=
72120=
35Answer(s): (a) 120; (b)
35