Question

Warren drives his car 220 miles and has a mean of a certain speed. If the mean speed had been 3 mph more, he could have traveled 231 miles in the same length of time. What was his mean speed?

Answer 1

Let t and t+3 be Warren's first and second speeds, respectively. Then:
220/t=231/t+3
220t+660=231t
t=60 mph as his mean speed
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