Examveda
Examveda

The rightmost non-zero digit of the number 302720 is

A. 1

B. 3

C. 7

D. 9

Answer: Option A

Solution(By Examveda Team)

(30)2720, we can write it as[(30)4]680
Or,[(10 × 3)4]680
The right most non-zero digit depends on the unit digit of [(3)4]680
Unit digit of [(3)4]680,
Or, (81)680
The unit digit of 81 is 1 so any power of 81 will always give its unit digit as 1
Thus, required unit digit is 1

This Question Belongs to Arithmetic Ability >> Number System

Join The Discussion

Comments ( 1 )

  1. NASREEN KHAN
    NASREEN KHAN :
    7 years ago

    Why we are not taking power less than 4 or greater than 4. How we should decide which pwer is give correct answer.

Related Questions on Number System