Solve Problems Using Systems in Three Variables
-Three Trains - $40 \mathrm { mph }$

Solve Problems Using Systems in Three Variables
-Three trains - one eastbound, one westbound, and one northbound - leave a city at the same time. The speed of the northbound train is 20 miles per hour greater than the speed of the eastbound train. After 3 hours, the distance between the westbound train and the eastbound train is 300 miles. Twice the speed of the westbound train is 60 miles per hour more than the speed of the northbound train. Find the speeds of the three trains.

A) eastbound, $40 \mathrm { mph }$ ; westbound, $60 \mathrm { mph }$ ; northbound, $60 \mathrm { mph }$
B) eastbound, $50 \mathrm { mph }$ ; westbound, $60 \mathrm { mph }$ ; northbound, $70 \mathrm { mph }$
C) eastbound, $30 \mathrm { mph }$ ; westbound, $70 \mathrm { mph }$ ; northbound, $60 \mathrm { mph }$
D) eastbound, $60 \mathrm { mph }$ ; westbound, $60 \mathrm { mph }$ ; northbound, $40 \mathrm { mph }$