Question

the present cost of a mobile phone is 15000. if its value decreases every year by 5%, find its cost 2 years ago

Answer 1

Answer:

16621 Rs

Step-by-step explanation:

Present cost = 15000

Rate of decrease= 5%

To calculate it's cost 2 years ago

let the cost 1 year ago is x

$x - \frac{5x}{100} = 15000 \\ \\ \frac{100x - 5x}{100} = 15000 \\ \\ \frac{95x}{100} = 15000 \\ \\ x = \frac{15000 \times 100}{95} \\ \\ x = 15789.47 \\ \\ x = 15790 \: rs$

One year before

$x - \frac{5x}{100} = 15790 \\ \\ \frac{100x - 5x}{100} = 15790 \\ \\ \frac{95x}{100} = 15790 \\ \\ x = \frac{15790\times 100}{95} \\ \\ x = 16621 \: rs$

Hope it helps you.