99 litres of gasoline oil is poured into a cylindrical drum of 60cm in diameter. How deep is the oil in the drum?

  35 cm

Step-by-step explanation:

The volume of a cylinder is given by ...

  V = πr²h

We want to find h for the given volume and diameter. First, we must convert the given values to compatible units.

  1 L = 1000 cm³, so 99 L = 99,000 cm³

  60 cm diameter = 2 × 30 cm radius

So, we have ...

  99,000 cm³ = π(30 cm)²h

  99,000/(900π) cm = h ≈ 35.01 cm

The oil is 35 cm deep in the drum.

When you're subtracting a number by a negative number (eg 4 – (-2)), the sign becomes positive because two negatives make a positive. (eg 4 – (-2) becomes 4+2)

also when writing it, make sure to correctly line up the decimals on both numbers when using the column method