Question

As smart phones have grown in popularity, regular cell phones have fallen out of favor. As a result, one electronics retailer estimates that 17% fewer regular cell phones will be sold every year. If the retailer sells 162,147 regular cell phones this year, how many will be sold 10 years from now?If necessary, round your answer to the nearest whole number.

Answer 1

Initially, the retailer sells 162,147 regular cell phones

The retailer stimates, that every year sales will fall a 17%

meaning that after one year, sales will be:

162,147 * (1-0.17) = 134582.01

then, after 2 years, sales will be:

134582.01 * (1-0.17) = 111703.0683

which is the same as

$162147\mleft(1-0.17\mright)^2=111703.0683$

in that way, we can create the following formula:

$162147\cdot(1-0.17)^y$

where y is time in years,

now, if we replace y = 10 we can obtain the solution we are looking for

$162147\cdot(1-0.17)^{10}=25158.795$

rounding to the nearest whole number: 25,159