A given whole number is doubled and 9 is added. If the number thus obtained is trebled, it becomes 171. If we subtract 3 from the given number, then the resultant will be divisible by

Correct option is D

Given:
Expression describing operations on an unknown number x: 3 × (2x + 9) = 171
Formula Used:
Linear equation in one variable.
Solution:
Let the original whole number be x.
Set up the equation based on the given wording:
3(2x + 9) = 171
2x + 9 = $$\frac{171}{3}$$​​
2x + 9 = 57
2x = 57 - 9
2x = 48
x = 24
The original given number is 24. We are asked to subtract 3 from it.
Result = 24 - 3 = 21.
Among the provided options (5, 2, 13, 7), 21 is exclusively divisible by 7.
Final Answer
So the correct answer is (d)