Find the smallest positive integer such that is a perfect square.
Answer and explanation
Correct answer: C. 5
- Step 1: Factorise: .
- Step 2: A perfect square needs every exponent even, so multiply by the primes with odd exponent: .
Answer
5.
Why not the others: 20: it uses itself. 10: an extra factor is included. 7: it adds the prime factors.
Practise more Properties of Integers.
Free questions with an explanation for every one, and full timed EJU Japan mock tests.