<PRE><B>Question 986973</B>
A speedboat travels at 60km/hr for two hours and then at 90km/hr for one hour. Find its average speed over the three hours:
:
we need to know how far, in how may hours. S = dist/time
Find the dist
2*60 = 120 km
1*90 =  90
--------------
total 210 km
:
S = {{{210/3}}}
S = 70 km/h over 3 hrs</PRE>