pzazz12 wrote:Steve traveled the first 2 hours of his journey at 40 mph and the remaining 3 hours of his journey at 80 mph. What is his average speed for the entire journey?
A. 60 mph
B. 56.67 mph
C . 53.33 mph
D. 64 mph
E. 66.67 mph
Average speed = Total Distance travelled during the journey / Total time taken
There are 2 cases :
Case 1 :
Traveled the first 2 hours of his journey at 40 mph
Hence distance travelled is (2*40) 80 miles
Case 2 :
3 hours of his journey at 80 mph
Hence distance travelled is (3*80) 240 miles
Thus total distance travelled is : (240 + 80)320 miles.
Total time taken is : (2+3) 5 hours.
Hence Average speed is : 320 / 5 = 64mph.