The value of a machine depreciates every year by 20%. If the present value of the machine be Rs. 160000, what was its value last year?
Let the value of machine last year = Z
∴ Present value = (100 – 20) % of Z
⇒ 160000 = 80% of Z
⇒ 160000 = Z × 80/100
⇒ Z = 160000 × 100/80
⇒ Z = 2000 × 100
⇒ Z = 200000