Jack went on a driving trip. For the first 785 miles, Jack spent a certain amount of time. In the next 785 miles, Jack increased the speed by 12 mph and for this reason, spent 10 fewer hours for this distance, How fast did Rohit drive for the second 785 miles.
who is Rohit?
Assuming you mean Jack...
\(T = \text{time spent driving first 785 miles}\\ s_1 = \dfrac{785}{T}\\ s_1+12 = \dfrac{785}{T-10}\)
\(\text{Substitute the first equation into the second and solve for } T\\ \text{Find }s_1 \text{ using the first equation}\\ s_2=s_1+12\)