At 2:00n p.m. Brad walks toward Lydia's house at 2 mph and Lydia walks toward Brad's house at 4 mph. When will they meet, if their homes are 9 miles apart?

They will meet at 3:30 p.m.

They would have walked for 1.5 hours.

(9) /( 2 + 4 ) = 1.5

B = distance Brad walks
L = distance Lydia walks
T = elapsed time
Distance = Rate times Time

B = 2 T
L = 4 T
B+L = 9

You can replace B and L with the first two equations and then solve for T. You have to add T to 2:00 p.m. to figure out the exact time that they meet.

After solving for T, you can solve for B and L, the distances that each travel.