Please explain all AT&T; @30% O, 9:47 PM webassign.net Your last submission is u

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Please explain



all AT&T; @30% O, 9:47 PM webassign.net Your last submission is used tor your score. 1-110 points SerCP11 2.P.003 My Notes Ask Your Teach 0 A person travels by car from one city to another with different constant speeds between pairs of cities. She drives for 40.0 min at 95.0 km/h, 20.0 min at 75.0 km/h, and 40.0 min at 40.0 km/h and spends 20.0 min eating lunch and buying gas. (a) Determine the average speed for the trip. km/h (b) Determine the distance between the initial and final cities along the route. km Need Help? Read

Explanation / Answer

(a)

Average speed for the trip is given as v = Total distance traveled / time spent

    Initial speed is v1 = 95 km/h

    Time spent with this speed is t1 = 40 min = 2/3 h

    Distance traveled with this speed is d1 = v1*t1 = (95 km/h)* (2/3 h ) = 63.33 km

    next speed is v2 = 75 km/h

    Time spent with this speed is t2 = 20 min = 1/3 h

   Distance traveled with this speed is d2 = v2*t2 = (75km/h)*(1/3 h)= 25 km

   Next speed is v3 = 40 km/h

    Time spent is t3 = 40 min = 2/3 h

     Then distance traveled is d3 = v3*t3 = (40km/h)*(2/3 h) = 26.66 km

   Time spent for eating is t4 = 20 min = 1/3 h

Then average speed is v =( d1 + d2 + d3 ) / (t1+t2 +t3 +t4)

v =(63.33 + 25 + 26.66) /( 2/3+ 1/3 + 2/3 h +1/3 )

v = 57.49 / km/h

b) Total distance traveled is d = d1 +d2 + d3 = 114.99 km

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