Question

Two trains leave the station at the same time, one heading east and the other west. The eastbound train travels

Answer 1

Answer:

80 miles per hour

Step-by-step explanation:

Eastbound

r = r - 12

t = 5 hours

d = d_e

Westbound

r = r

t = 5 hours

d_w = 850 - d

The two distances add up to 850 miles

d_w + d_e = 850 miles

(r * t)_w + ( (r -12)*5 ) = 850 miles

r*5 + (r - 12) * 5 = 850                     Pull out 5 as a common factor

5 * ( r + r - 12)  = 850                       Divide by 5

(r + r - 12) * 5/5 = 850/5                  Do the cancellation

2r - 12 = 170                                     Add 12 to both sides

2r - 12 + 12 = 172 + 12

2r = 184                                           Divide by 2

r = 92

r = the westbound train     =  92 mph

r - 12 = The eastbound train  = 80 mph