Define variables

Let the principal amount deposited be $P$. Since $x\%$ of the salary is deposited, $P = \frac{x}{100} \times 80000 = 800x$.

$P = 800x$

Apply Interest Formula

The accumulated amount $A$ is the sum of principal and simple interest. The formula is $A = P(1 + \frac{RT}{100})$. Substituting $R=15\%$ and $T=3$ years:

$17400 = P(1 + \frac{15 \times 3}{100}) = P(1 + 0.45) = 1.45P$

Calculate Principal P

Solving for $P$, we get $P = \frac{17400}{1.45}$. Calculating this gives $P = 12000$.

$P = 12000$

Solve for x

Now substitute $P = 12000$ back into the equation $800x = 12000$. Solving for $x$ gives $x = \frac{12000}{800} = 15$.

$x = 15$