Problem #$3$: In a mixing vat there are initially $100$ litres of volatile liquid. $1$ litres of fresh liquid are added per hour, but $5\%$ of

the current content of the vat is lost each hour due to evaporation. How many litres of liquid are there after $4$

hours?

Problem #$3$:

Enter your answer symbolically,

as in these examples

Submit Problem #$3$ for Grading