Answer:
90mph
Step-by-step explanation;
if an object travels 30 miles in the first part of an hour, and the speed is constant, then we can assume 30*3=90
in the first third, it went 30 mi, in the second it went 30mi, and in the last part it went 30 mi
30+30+30=90
or you could do 30* the denominator (in this case its 3), so 30*3=90
Sorry if this doesn't make sense, hope it helps though!