Q:

A train left Podunk and traveled west at 70 km/hr. Two hours later, another train left Podunk and traveled east at 90 km/hr. How many hours had the first train traveled when they were 1420 km apart

Accepted Solution

A:
Answer:The first train going west traveled by 7 hours and 45 minutes  Step-by-step explanation:Given as :The speed of west going train = 70 kmphThe speed of east going train  = 90 kmphDistance between both the train is 1420 km Let the distance cover by east going train = x km So, The distance cover by west going train = (1420 - x) kmThe west going train travel for T hour And The east going train travel for ( T + 2 ) hourNow, From Distance = speed × timeFor east going train x = 90 × ( T + 2 )Or, x = 90 T + 180  For west going train 1420 - x = 70 × T So, from above equations :1420 - (90 T + 180 ) = 70 TOr, 1420 - 180 = 70 T + 90 TOr, 1240    =  160 T∴  T = [tex]\frac{1240}{160}[/tex] So, T = 7.75 hoursOr,  T = ( 7 + [tex]\frac{75}{100}[/tex] ) hoursOr,  T = (7 + [tex]\frac{3}{4}[/tex] ) hoursOr, T = 7 hours and 45 minutes Hence The first train going west traveled by 7 hours and 45 minutes   Answer