Multiple choice general knowledge math & puzzles

Find the greatest number of five digits, which is exactly divisible by 7, 10, 15, 21 and 28.

  1. 99840

  2. 99900

  3. 99960

  4. 99990

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The LCM of 7, 10, 15, 21, and 28 is 420. To find the greatest five-digit number, divide 99999 by 420 (remainder 39). 99999 - 39 = 99960. This number is exactly divisible by all the given factors, unlike the other options.