Question

A man says, "I am thinking of a number. When I divide it by 3 and then add 5, my answer is twice the number I thought of". Find the number.

Answer 1

Let the number thought of by the man be 'x'.
So, ATQ:
⇒ $\frac{x}{3}+5=2x$
Transposing x/3 to RHS, we get
⇒ 5 = $2x-\frac{x}{3}$
⇒ 5 = $\frac{6x-x}{3}$
⇒ 5 = $\frac{5x}{3}$
Multiplying both sides by 3, we get
⇒ $5\times 3=\frac{5x}{3}\times 3$
⇒ 15 = 5x
Dividing both sides by 5, we get
⇒ $\frac{15}{5}=\frac{5x}{5}$
⇒ x = 3
Thus, the number thought of by the man is 3.