Question

A machine depreciates every year at the rate of 20% of its value at the beginning of the
year. The machine was purchased for * 2,50,000 when new, and the scrap value realised when
sold was 1,28,000. Find the number of years that the machine was used.(using compound interest )





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Answer 1

Answer:

∴ Value of machine after n years = Its value when new (1−  r/ 100 r  )n

⇒Rs.128000=Rs.250000(1−  20/100  )  n

⇒ Rs.128000 / Rs.250000 =(  80/100  )  n  =(  4/5  )  n

On simplifying, we get :

(  4/5 ) 3 =( 4/5)n

⇒n=3years