A car is traveling from New Haven to Philadelphia. It takes 1 hour and 24 minutes to drive 85 miles from New Haven to New York City. What was the average speed?
First I converted the hour and $24$ min into a decimal: $$1 \space hour \space and\left(\frac{24}{60}\right) min$$ $$=1.4 \space hrs.$$ Then taking the distance divided by time $$\frac{85}{1.4}=60.71 \space mph$$
Am I correct?
Yes, you are correct. As a sanity check, you can see that if the car travels at an average speed of 60.71 mph for 1.4 hours, it covers a distance of $60.71 \times 1.4 \approx 85$ miles.