The digit in the unit’s place of the number represented by (7⁹⁵ – 3⁵⁸) is:

Question

Question

This question was previously asked in

RRC Group D Previous Paper 2 (Held On: 18 Sep 2018 Shift 1)

Answer 1

Given:

(795 – 358)

Concept used:

Cyclicity of 7 is 4

Cyclicity of 3 is 4

Calculation:

7⁹⁵ = 7^{(4 × 23) + 3} = 1 × 7³ = 343

⇒ Unit digit of 7⁹⁵ = 3

3⁵⁸ = 3^{(4 × 14) + 2}= 1 × 3² = 9

⇒ Unit digit of 3⁵⁸ = 9

Unit digit of (7⁹⁵ – 3⁵⁸) = 3 – 9 = -6 or 10 - 6 = 4

∴ Unit place will be 4

Note: 3 - 9 = -6 because we have to find the unit digit. whenever the result is negative add 10 in it.