What is the smallest number which is when increased by 5 is divisible by 18, 30, 36 and 24?

Correct option is A

Given:
We are to find the smallest number which, when increased by 5, is divisible by 18, 30, 36, and 24.
Solution:
Let the required number be x.
Then,
x + 5 = LCM of (18, 30, 36, 24)
x =  LCM(18, 30, 36, 24) - 5
Find the LCM of 18, 30, 36, and 24
​$$18 = 2 \times 3^2\\ 30 = 2 \times 3 \times 5\\36 = 2^2 \times 3^2\\ 24 = 2^3 \times 3\\$$​​
​$$\text{LCM} = 2^3 \times 3^2 \times 5 = 8 \times 9 \times 5 = 36$$​​
​$$x + 5 = 360\\ \Rightarrow x = 360 - 5 = 355$$​​