3152gs wrote:
At 1:30 A passes B meaning that during that time they started heading together to town Y with their respective speeds.
At 3:15 A reaches Y but B reaches some other point 35 miles away from Y. Let the distance travelled by B from 1:30 to 3:15 or during 1.75 hr be x.
That means A has travelled whatever B has travelled plus 35 miles.
Putting all these together,
Distance travelled by B during this 1.75 hour = x
Distance travelled by A during this 1.75 hour = x + 35
Speed (B) = distance travelled/time taken =x/1.75
Speed (A) = (x+35)/1.75
Now we are given that,
Speed (A) = 1.25*Speed (B),
(x+35)/1.75 =1.25*(x/1.75)
1.25*x - x = 35
x=35/0.25 = 140
Now plug this value into speed(A) above which gives us 100 mph.
actually it will be 1.45 hour not 1.75 hour1:30 - 3:15 = 1 hour 45 mins = 60+45 mins = 105 mins = 105/60 hr = 1.75hr