math
posted by israel .
how do i solve this: a Train leaves Poughkeepsie to grand central station in NYC at an average speed of 40 mph. a half hour later an express train leaves poughkeepsie station to NYC at a speed of 50 mph. both trains arrive at NYC the same time. based on this info calculate the distance between poughkeepsie and NYC

math 
Reiny
let the distance be x miles
time for first train = x/40
time for second train = x/50
x/40  x/50 = 1/2
times 200
5x  4x = 100
x = 100
Distance is 100 miles
check: to go 100 miles at 40 mph takes 100/40 hrs = 2.5
to go 100 miles at 50 mph takes 100/50 = 2hrs.
Does it take 1/2 less ? YES
Respond to this Question
Similar Questions

Math Word Problem
A metra commuter train leaves Union Station in Chicago at 12 noon. Twp hours later an Amtrak train leaves on the same track, traveling at an average speed that is 50 miles per hour faster than the Metra train. At 3PM the Amtrak train … 
pre algebra
train A leaves a station at 1:15 PM,traveling 60 mph.Train B leaves the same station, in the same direction as train A,15 minutes later.If train B travels 90mphm when (clock time)will train B catch up to train A and how far down the … 
Algebra 2 (Distance Problem)
A train leaves Union Station for Central Station, 216 km away, at 9 A.M. One hour later, a train leaves Central Station for Union Station. They meet at noon. If the second train had started at 9 A.M., and the first train at 10:30 A.M., … 
college physics
An express subway train passes through an underground station. It enters at t = 0 with an initial velocity of 23.0 m/s and decelerates at a rate of 0.150 m/s2 as it goes through. The station in 210 m long. (a) How long is the nose … 
physics
An express subway train passes through an underground station. It enters at t = 0 with an initial velocity of 23.0 m/s and decelerates at a rate of 0.150 m/s2 as it goes through. The station in 210 m long. (a) How long is the nose … 
Math
A train leaves a station and travels north at a speed of 45mph. Four hours later, a second train leaves on a parallel track and travels north at 105 mph. How far from the station will they meet? 
physics
An express subway train passes through an underground station. It enters at t = 0 with an initial velocity of 23.5 m/s and decelerates at a rate of 0.150 m/s2 as it goes through. The station in 215 m long. (a) How long is the nose … 
algebra
A train leaves a station and travels north at a speed if 50 mph. Five hours later, a second train leaves on a parallel track and travels north at 175 mph. How far from the station will they meet? 
college algebra
A freight rain leaves a station and travels north at a constant rate of 60 mph. One hour later a passenger train leaves the same station traveling north on a parallel track at 80 mph. How long will it take for the passenger train to … 
math
A train leaves a station and travels north at a speed of 105 mph. Two hours later, a second train leaves on a parallel track and travels north at 135 mph. How far from the station will they meet?