prepratory math

Question

Two trains leave stations 390

 miles apart at the same time and travel toward each other. One train travels at 80

 miles per hour while the other travels at 70

 miles per hour. How long will it take for the two trains to meet?

Do not do any rounding.

Answer 1

390/(70+80) = 390/150 = 39/15 = 13/5 = 2.6 hours

in 13/5 hours the train going 70mph will go 70 x 13/5 = 14x13 = 182 miles

the train going 80 mph will go 80 x 13/5 = 16x13 = 208 miles

182 + 208 = 390 miles

exactly 2.6 hours to meet. = 2 hours and 36 minutes