Question

The function f (x) = .85x+3.99 models the total cost of purchasing x key chains from an internet company that charges shipping the function g (x) = 1.10x models the total purchasing of x number of the same key chains from an company that does not charge shipping. Rounding to the nearest whole number what is the best approximation of the number of key chains for which the two companies charge the same amount?

Answer 1

16 key chains

Explanation:

Given

`f(x) = 0.85x + 3.99` ---company A

`g(x) = 1.10x` --- company B

Required

Value of x when
`f(x) = g(x)`

We have:

`f(x) = g(x)`

`0.85x + 3.99 = 1.10x`

Collect like terms

`0.85x - 1.10x = -3.99`

`-0.25x = -3.99`

Solve for x

`x = (-3.99)/(-0.25)`

`x = 15.96`

`x= 16` --- approximated