I went to Washington DC from Boston, starting out with 55 mph speed. Then, the speed changed to 75 mph. I traveled 630 miles in 10 hours. At what time did I start driving faster? (Example: 1:05 p.m)

D

Step-by-step explanation:

10*20=200

200 + 1020= 1220

Works for the first one

20*20=400

400+ 1020=1420

Works for the second one

30*20=600

600+1020=1620

Works for the third one, and all the others one so forth.

You take the number on the left (10, 20, 30, 40, 50, 60, 70) and times it by 20, replacing the x in the equation with the number on the left side of the table. Then you add the number from said equation to result of the multiplication from the first step.