Tank C and Tank D had some oil in the ratio 7 : 5. After 20 litres of oil was transferred from Tank C to Tank D, the volume of oil in Tank D became 5 times as much as in Tank C. How much oil were there in the two tanks in all?
| |
Tank C |
Tank D |
Total |
Before |
7x1 =
7 u |
5x1 =
5 u |
12x1 =
12 u |
| Change |
- 20 |
+ 20 |
|
After |
1x2 =
2 u |
5x2 =
10 u |
6x2 =
12 u |
The total volume of oil in the tanks remained unchanged. Make the total volume at first and in the end the same. LCM of 6 and 12 is 12.
Amount of oil transferred from Tank C to Tank D
= 7 u - 2 u
= 5 u
5 u = 20
1 u = 20 ÷ 5 = 4
Total volume of oil in two tanks
= 12 u
= 12 x 4
= 48 ℓ
Answer(s): 48 ℓ
