One morning, Justin drove 5 hours before stopping to eat lunch at chick-fil-A. After lunch, he increased his speedy by 10 mph. If he completed 310-mile trip in 9 hours of driving time, how fast did he drive in the morning?

30 mph

Step-by-step explanation:

Let the morning speed be represented by s.

Then the total distance drivern is 310 mi and this is equal to

5s + 4(s + 10):

5s + 4s + 40 = 310, or

    9s             = 270

Solving for s, we get s = 270/9 = 30

Then s + 10 = 40

He drove 30 mph in the morning and 40 mph in the afternoon.

Check:  (30 mph)(5 hrs) + (40 mph)(4 hrs) =  310 miles.  CORRECT

unpaid balance is : $149.99-$50 = $99.99 new balance = 149.99+2.62-50 = $102.61 finance charge = 99.99- 0.21/12= $1.75 new balance = 99.99+1.75 = $101.74 average daily balance method average daily balance= 3399.70/30 = $113.32 finance charge = $ 0.21/12ă—113.32 = $1.98 new balance = $149.99-50+1.98 = $101.97