A professional writer decides to judge the value of her laptop by the number of times she presses its keys before it breaks. The value V depends on the number of keypresses, k, according to the
formula:
V = 1200 -0.00002k
After one year, the value of her laptop is between $803.20 and $899.20.
What is the corresponding range of keypresses?.

D.)

15040000 <= k <=19840000

Step-by-step explanation:

V = 1200 -0.00002k

Value V after one year falls in the range of $803.20 and $899.20.

Let's substract these values from 1200.

1200-803.20=396.80

1200-899.20=300.80

So it means that

0.00002k= 396.80

And

0.00002k= 300.80

So

0.00002k= 396.80

K= 396.80/0.00002

K= 19840000

And

0.00002k= 300.80

K = 300.80/0.00002

K= 15040000

So range is between

15040000 <= k <=19840000