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GATE 2018 EC – Question 3

General Aptitude · Quantitative Aptitude: Arithmetic and Number Computation · 1 mark · Multiple choice

If the number 715■423 is divisible by 3 (■ denotes the missing digit in the thousandths place), then the smallest whole number in the place of ■ is ________.

  1. 0
  2. 2
  3. 5
  4. 6

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Correct answer: (B) 2

Explanation

A number is divisible by 3 when its digit sum is. The known digits sum to $7+1+5+4+2+3=22$, and $22+x$ must be a multiple of 3, so the smallest whole number is $x=2$.