The dimension of a rectangular tank are 2m by 7m by 11m. If its volume is equal to that of a cylindrical tank…

Analyze the question: The rectangular tank has volume equal to that of a cylindrical tank. We need the base radius of the cylinder.

Concept:

• Volume of cuboid = l × w × h
• Volume of cylinder = πr²h

Solution:

Volume of the rectangular tank = 2 × 7 × 11 = 154 m³

The question says the cylinder's height is "4cm", but that looks like a typo. Let's test both readings.

If h = 4 m:

πr²h = 154 (22/7) × r² × 4 = 154 r² = 154 × 7 / (22 × 4) = 1078 / 88 = 12.25 r = 3.5 m = 3½ m

This matches option C exactly.

If h = 4 cm (0.04 m) literally:

r² = 154 / ((22/7) × 0.04) = 154 × 7 / (0.88) = 1225 r = 35 m

That is not among the options, so the intended height must be 4 m.

Check: (22/7) × 3.5² × 4 = (22/7) × 12.25 × 4 = 3.14... precisely: 22 × 1.75 × 4 = 154 ✓

Answer: The base radius is 3½ m, which is option C.

Tip: When the numbers include 7 and 22/7, expect the radius to come out as a multiple of 7 or 3.5. Also check units: if the literal reading gives an answer not among the options, look for a typo in the question, such as "cm" instead of "m".