At the end of which year does the machine's book value first fall below ₹2,00,000?

Explanation

1. 01

   $6{,}00{,}000 - 70{,}000n < 2{,}00{,}000 \Rightarrow n > 5.71$.

2. 02

   After 5 years it is ₹2,50,000; after 6 years, ₹1,80,000. So the end of year 6.