Answer:
He  needs to drive for 9 days to  to save enough money to buy the television.
Step-by-step explanation:
The per day salary of Ken = $ 100
Also, he receives $0.50 for per miles he drives.
Now, in a day if Ken drives 400 miles.
So, the amount he receives as his per mile rate  = 400 x (Per mile cost)
= 400 x ( $0.50) = $200
So, Ken's per day income
= FIXED AMOUNT Â + Amount he receives driving 400 miles a day
= $100 + Â $200 Â = $300
⇒ In 1 day , Ken earns $300.
Now, he wants to purchase a TV costing $2500
Let us assume he saves enough money in m days.
⇒ SAVINGS in m DAYS = COST OF THE TV
⇒  m  x ( $300)  = $2500
⇒ m  = $2500/ $300 = 8.33
or, m = 8.33
Now, the greater whole number next  to 8.33 = 9
Hence he  needs to drive for 9 days to  to save enough money to buy the television.