SSC CHSL 2021 PYQ — Question 62

The correct answer is Option 3 i.e. 8.

Concept USed:

If a number is divisible by 72, that means it is divisible by both 8 and 9.

Divisibility of 8: If the last three digits of a number is divisible by 8, the whole number is divisible by 8.

Divisibility of 9: If the sum of the digits of a number is divisible by 9, the number is divisible by 9.

Explanation:

According to the given question,

The given number is 489x 6378y,

For a number to be divisible by 8, 78y should be divisible by 8.

⇒ y = 4

Also for the number 489x 63784 to be divisible by 9, sum of digits, i.e.,

(4 + 8 + 9 + x + 6 + 3 + 7 + 8 + 4) should be divisible by 9

⇒ (49 + x) should be divisible by 9

 ⇒ x = 5

Now the required value = ${\sqrt{8x+6y}}$ 

⇒ ${\sqrt{8 \times 5 +6 \times 4}}$

⇒ ${\sqrt{40 + 24}}$

⇒ ${\sqrt{64}}$ = 8

Hence ther required answer is 8.