LCM of 10, 15 and 20 is
30
60
90
180
Step 1: Write prime factors.
\(10 = 2 \times 5\)
\(15 = 3 \times 5\)
\(20 = 2 \times 2 \times 5 = 2^2 \times 5\)
Step 2: For LCM, take each prime with the highest power.
From the lists above:
Prime \(2\): highest power is \(2^2\).
Prime \(3\): highest power is \(3^1\).
Prime \(5\): highest power is \(5^1\).
Step 3: Multiply these together.
\(2^2 = 4\)
\(4 \times 3 = 12\)
\(12 \times 5 = 60\)
Answer: LCM \(= 60\). So the correct option is B.