Find the greatest 5 -digit number that can be divisible by 18,15 and 21 .

Correct option is D

Given:

Greatest 5 -digit number that can be divisible by 18,15 and 21 .

Solution:

LCM of 18, 15, and 21:

​$$2^1×3^2×5^1×7^1$$

​​2 × 9 × 5 × 7 = 630

greatest 5-digit number divisible by 630

The greatest 5-digit number is 99999.

Divide 99999 by 630 and find the quotient:

Quotient = $$[\frac{99999}{630}]$$ = 158

Multiply 158 by 630 to find the largest 5-digit multiple

158 × 630 = 99540

So, the greatest 5-digit number that is divisible by 18, 15, and 21 is 99540.

Thus, correct option is (d)