Question

Krishna purchased an old scooter for 8000. If
its cost after 2 years is 6480, what is the rate
of depreciation ?​

Answer 1

Answer:

Compound interest on a sum of Rs 8000 at a certain rate of interest compounded annually for 2 years is Rs 6480

Let rate of depreciation = r %

We know formula for compound interest :

Amount = P(1 +r100)t , Here P = 8000 , t = 2 , Compound interest = 6480 , So

8000 (1 + r100)2 = 6480⇒(1 + r100)2 = 64808000 ⇒(1 + r100)2 = 81100 ⇒(1 + r100)2 = 92102 ⇒(1 + r100)2 = (910 )2⇒1 + r100= 910 ⇒r100= 910 − 1⇒r100= 9 − 1010 ⇒r100= − 110 ⇒r= − 110 ×100

⇒r= − 10

ANSWER : 10 %