All Exams Test series for 1 year @ ₹349 only
Question

The least number by which 294 must be multiplied to make it a perfect square, is:

This question was previously asked in
RRB NTPC 2019 CBT 1 Question Paper (8-Mar-2021) (Shift 2)
The correct answer is
6

Finding the Least Number for a Perfect Square

To find the least number by which 294 must be multiplied to make it a perfect square, we first find the prime factorization of 294.

Prime Factorization of 294

Step 1: Divide 294 by the smallest prime number, 2.

$294 \div 2 = 147$

Step 2: Divide 147 by the next smallest prime number, 3.

$147 \div 3 = 49$

Step 3: Divide 49 by the prime number 7.

$49 \div 7 = 7$

Step 4: Divide 7 by 7.

$7 \div 7 = 1$

The prime factorization of 294 is $2 \times 3 \times 7 \times 7$, which can be written as $2^1 \times 3^1 \times 7^2$.

Identifying the Multiplier

For a number to be a perfect square, all the exponents in its prime factorization must be even.

  • The prime factor 2 has an exponent of 1 (odd).
  • The prime factor 3 has an exponent of 1 (odd).
  • The prime factor 7 has an exponent of 2 (even).

To make the exponents of 2 and 3 even, we need to multiply by one more 2 and one more 3.

The least number required is the product of the prime factors with odd exponents, raised to the power of 1.

Required multiplier $= 2 \times 3 = 6$.

Verification

Multiplying 294 by 6:

$294 \times 6 = (2^1 \times 3^1 \times 7^2) \times (2^1 \times 3^1)$

$= 2^{(1+1)} \times 3^{(1+1)} \times 7^2$

$= 2^2 \times 3^2 \times 7^2$

$= (2 \times 3 \times 7)^2$

$= 42^2$

Since $42^2$ is a perfect square, the least number by which 294 must be multiplied is 6.

Was this answer helpful?

Similar Questions

  1. How many factors of $2^{2} \times 3^{1} \times 5^{2} \times 7^{1}$ are divisible by 50 but not by 100?
  2. What is the total number of odd and even divisors of 120, respectively?
  3. The Government of India Constituted Narcotics Control Bureau in _____.
  4. Which of the following expresses the prime factorisation of 54?
  5. How many factors of $2^7 \times 3^4 \times 5^3 \times 7$ are even?
  6. How many factors does the number 12288 have?
  7. The number of factors of 4200 are:

Important Questions from Multiples and Factors

  1. Express 486 as a product of powers of prime factors.

  2. Let p, q, r and s be positive natural numbers having three exact factors including 1 and the number itself. If q > p and both are two-digit numbers, and r > s and both are one-digit numbers, then the value of the expression \(\frac{p-q-1}{r-s}\)  is:

  3. Find the greatest three-digit number which is a multiple of 8.

  4. The smallest prime number is:

  5. The sum of three consecutive multiples of 7 is 840. The smallest of these multiples is:

Need Expert Advice?
Upcoming Exams
RRB NTPC
September 27, 2026
Test Series
RRB NTPC img
Railways
RRB NTPC Under Graduate 2026 New Mock Test Series
1580 Tests 2 Tests Free
460 Attempts
4.3(493)
English, Hindi, Telugu +7 More

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App