Question

Find the smallest square number from among the given options, which is divisible by each of 8, 15 and 20.

• A. 3600
• B. 6400
• C. 14400
• D. 4900

Answer 1

Answer:

A. 3600

LCM of 8, 15, 20,

⇒ 8 = $2\times{2}\times{2}$

⇒ 15 = $3\times{5}$

⇒ 20 = $2\times{2}\times{5}$

LCM = $2\times{2}\times{2}\times{5}\times{3}$

To make perfect square then each prime factor has even powers

LCM = $2\times{2}\times{2}\times{2}\times{5}\times{5}\times{3}\times{3}$ = 3600

∴ 3600 is the smallest number from among the given options, which is divisible by each of 8, 15 and 20.