Question

The price of a PC has been decreasing every year by a constant percentage over the last 4 years. If cost of a PC was ₹50000 4 years ago and it costs ₹32805 now, find the yearly rate of decrease.
(A) 8% (B) 5% (C) 10% (D) 15%​
Please provide step by step explanation. ​

Answer 1

Answer:

10 %

Step-by-step explanation:

given that percentage decrease is constant , let percentage decrease be y

now , 1st amount = 50000 and final amount = 32805

(so it gradually keeps on decreasing at a fixed percentage )

we can calculate this by

multiplying the 1st amount with (the constant decrease rate)^4 = final amount

here 4 is with respect to the time period which is 4 years

now we have the equation as

50000 × (x^4/100^4) = 32805

5 × x^4/10000 = 32805

x^4 = 6561 × 10^4

x^4 = (9×10)^4

x = 90

here x = 100 - y

therefore y = 10