Time distance and rate

Question

Mrs. Namvar drives from Andover to Toronto and then returns back home the same way. She travels at 55 miles per hour going to Toronto. On her way back to Andover, she travels at 70 miles per hour. It took her 2 hours less going to Andover

Answer 1

distance  = rate x time

 

distance = 55 t = 70(t-2)

 

55t = 70t - 140

 

0 = 70t - 140 - 55t

 

0 = 15t - 140

 

140 = 15t

 

t = 140/15 = 28/3 hr = 9 and 1/3 hours = 9 hours and 20 minutes

 

t-2 = 7 hours and 20 minutes = 7 and 1/3 hours = 22/3 hr

 

28/3 * 55 = 513 and 1/3 miles

 

22/3 * 70 = 513 and 1/3 miles