In a shop, the number of cartons of lemon juice sold was
14 the number of cartons left. When 21 more cartons were sold, the total number of cartons sold was 9 less than
710 the number of cartons the shop had at first. How many cartons were there at first?
|
Sold |
Left |
Total |
Before |
1x2 = 2 u |
4x2 = 8 u |
5x2 = 10 u
|
Change |
+ 21 |
- 21 |
|
After |
2 u + 21 |
8 u - 21 |
10 u |
Comparing the total number of cartons sold and the total number of cartons at first |
7x1 - 9 = 7 u - 9 |
|
10x1 = 10 u |
The total number of cartons is repeated. Make the total number of cartons the same. LCM of 5 and 10 is 10.
The number of cartons sold in the end is repeated.
7 u - 9 = 2 u + 21
7 u - 2 u = 21 + 9
5 u = 30
1 u = 30 ÷ 5 = 6
Number of cartons at first
= 10 u
= 10 x 6
= 60
Answer(s): 60