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You travel 20.0 mph for 0.500 hour, 40.0 mph for 1.00 hour, 30.0 mph for 0.500 hour, and 50.0 mph for 2.00 hours. What is the average speed?

User Silk
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1 Answer

4 votes
The answer is 41.25 mph.

The average speed (v) can be expressed as:
v = D/T
where
D is total distance: D = d1 + d2 + d3 + d4
T is total time: T = t1 + t2 + t3 + t4

Now let's calculate distances using the formula: d = v * t:
d1 = v1 * t1 = 20.0 * 0.500 = 10 mi
d2 = v2 * t2 = 40.0 * 1.00 = 40 mi
d3 = v3 * t3 = 30.0 * 0.500 = 15 mi
d4 = v4 * t4 = 50.0 * 2.00 = 100 mi

Thus, the average speed is:

v= (D)/(T)= (d1 + d2 + d3 +d4)/(t1+t2+t3+t4) = (10+40+15+100)/(0.500+1.00+0.500+2.00)= (165)/(4) = 41.25 mph
User Wojteks
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8.8k points