Problem 16

Explanation

Let Farhat's salary be $F$ and Abas's salary be $A$.

The initial ratio of their salaries is given as $2 : 3$:

After both receive a salary increase of $40,000$ rupiah, the ratio becomes $5 : 7$. To simplify calculations, we will work in thousands (removing the last 3 zeros temporarily), so the increase is $40$.

We can write this equation as:

Cross-multiply the equation:

Substitute $F = \frac{2}{3}A$ into the equation:

Group the terms containing $A$ on one side and the constants on the other:

Multiply both sides by 3 to find the value of $A$:

Since we used units of thousands, Abas's actual salary is $240,000$ rupiah.

Thus, Abas's current salary is $240,000$ rupiah.