Question

Jane travels7 mph less than2 times as fast as Mike. Starting at the same point and traveling in the same direction, they are198 miles apart after6 hours. Find their speeds.

Answer 1

Let:

Vj = Speed of jane

Vm = Speed of mike

d = distance

t = time

Jane travels 7 mph less than 2 times as fast as Mike, therefore:

Vj = 2Vm - 7

Remeber:

distance = speed*time

Distance traveled by mike:

d=Vm*t = Vm*6

Distance traveled by jane:

d + 198 = Vj*6

where:

Vj = 2Vm - 7

d + 198 = (2Vm-7)*6

Now, let:

d=Vm*6 (1)

d + 198 = (2Vm-7)*6 (2)

Replace (1) into (2)

6Vm + 198 = 12Vm - 42

Subtract 6Vm from both sides:

6Vm + 198 - 6Vm = 12Vm - 42 - 6Vm

198 = 6Vm - 42

Add 42 to both sides:

198 + 42 = 6Vm - 42 + 42

240 = 6Vm

Divide both sides by 6:

240/6 = 6Vm/6

40 = Vm

Vm = 40mph

Replace Vm into this equation Vj = 2Vm - 7 :

Vj = 2(40) - 7 = 80 - 7 = 73mph