Avg spd? a bus travels 3 hours at avg spd 50mph. how much longer must it trav at 60mph so avg spd is 52mph?

Question

Avg spd? a bus travels 3 hours at avg spd 50mph. how much longer must it trav at 60mph so avg spd is 52mph?

Answer 1

58 minutes

Answer 2

30 minutes.

Answer 3

It will take 45 minutes at 60 mph to attain an average speed of 52.

Here's your formula:

x represents time in hours

50*3 = distance already traveled

60 = new rate of speed

52 = new desired average speed

((50*3)+(60x)) / (3+x) = 52 (distance already traveled + new rate times the extra time all divided by total time needed  equals new average )

150 + 60x = 52*(3+x) (multiply both sides by x+3)

150 + 60x = 156 + 52x (simplification)

8x = 6

x = .75 (3/4ths of one hour, 45 minutes)

Answer 4

45 mins    (follow the formula)

[(50*3)+(x*60)]/(3+x) = 52

Answer 5

45 min

195miles/225min x 60=52

Answer 6

1 hour= 52.5mph (close enough)

210 miles total /4h= 52.5