Raju has turpentine oil in 5 containers each of 20 L size. He fills them in 10 cans of 5L, 10 cans of 2 L and rest in 1 L cans. Number of 1 L cans filled is:

5 containers each of 20 L → Total = 5 × 20 = 100 L
Filled into:

10 cans of 5 L

10 cans of 2 L

Rest in 1 L cans

Formula used:
Remaining volume = Total volume − (volume of 5 L cans + volume of 2 L cans)

Solution:
Volume in 5 L cans = 10 × 5 = 50 L
Volume in 2 L cans = 10 × 2 = 20 L
Remaining = 100 − (50 + 20) = 30 L

Number of 1 L cans = 30