SSC CGL 2020 PYQ — Question 69

SSC CGL Tier II - Quant - 15 Nov 2020 • Quantitative Aptitude • Q69

When 1062, 1134 and 1182 are divided by the greatest number x, the remainder in each case is y. What is the value of (x - y)?

Show answer & explanation

Correct answer: B

Explanation

 The correct answer is option 2 i.e. 18

Concept

We need to find HCF. HCF can be calculated by taking the difference of the numbers when they leave same remainder when divided by same number. When A, B and C are divided by a greatest number 'K' and leaves the same remainder each time, then the value of K can be calculated by (A - B) (B - C) and (A - C)  

Application

We need to take the differences of each number to calculate HCF

= (1134 - 1062), (1182 - 1134) and (1182 - 1062)

1134 - 1062 = 72 

1182 - 1134 = 48 

1182 - 1062 = 120 

Upon Prime Factorization 

72 = 23 × 32 

48 = 24 × 3 

120 = 23 × 3 × 5 

To calculate HCF, we need to take numbers which are common in each of the numbers

Thus we get =  23 x 3 = 24

Therefore, the greatest number or x = 24

When we divide 1134 by 24, we get remainder as 6 which is y

Therefore = x - y

= 24 - 6 = 18