Answer:
speed of Jim's train = 35 mi/h
speed of Sarah's train = 35 +20 mi/h = 55 mi/hour
Explanation:
Let the speed of Jim's train be x mi/h
Given, Sarah and Jim leave a train station at the same time traveling 20mi/h faster that Jim’s train.
speed of Sarah's train = x + 20 mi/h
we know distance = speed * time
time = 3 hours
distance traveled by Sarah's train = 3*(x+20) = 3x+60 miles
distance traveled by Jim's train = 3*x = 3x miles
It is not given that if trains are moving in same or opposite direction.
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if they are travelling in same direction
Then, then distance between them = total distance traveled by
faster train - total distance traveled by
slower train = 3x +60 -3x = 60 miles
which is wrong as the two trains are 270 miles apart
hence, they are travelling in opposite direction
In this case
distance between them = total distance traveled by
faster train + total distance traveled by
slower train = 3x +60 + 3x = 6x + 60 miles
given that the trains are 270 miles apart
6x + 60 miles = 270 miles
6x = 270 - 60 = 210
x = 210/6 = 35
Thus, speed of Jim's train = 35 mi/h
speed of Sarah's train = 35 +20 mi/h = 55 mi/hour