Question 1162390
he speed of a freight train is 30 mph slower than the speed of a passenger train. The freight travels 140 mi in the same time that it takes the passenger train to travel 210 mi. Find the speed of each train.
<pre>Let speed of freight train be S
Then speed of passenger train = S + 30.
Freight and passenger trains' times: {{{matrix(1,3, 140/S, and, 210/(S + 30))}}}, respectively 
As their times are the same, we get the following DISTANCE equation: {{{matrix(1,3, 140/S, "=", 210/(S + 30))}}}
{{{matrix(1,3, 2/S, "=", 3/(S + 30))}}} ------- Factoring out GCF, 70, in numerator
3S = 2(S + 30) ------ Cross-multiplying
3S = 2S + 60
3S - 2S = 60
Speed of freight train, or {{{highlight_green(matrix(1,4, S, "=", 60, mph))}}}
You should now be able to find the passenger train's speed.