Answer:
Van: 36 mph.
Plane: 102 mph.
Step-by-step explanation:
x = speed of van
y = common time value
(3x - 6) * y = 204 // plane
x * y = 72 // van
3xy - 6y = 204 // plane simplified
We can now substitute 72 for xy in the equation above.
3*72 - 6y = 204 --> 216 - 6y = 204
We now subtract 216 from both sides.
-6y = -12
We now divide both sides by -1 to get rid of the negative sign & then divide both sides by 6 to simplify.
y = 2
If x*y = 72, then x = 72/y = 72/2 = 36.
Thus, the speed of the van is 36 mph.
We can find the speed of the plane by using the equation from earlier, 3x - 6.
3x - 6 = 3*36 - 6 = 108 - 6 = 102.
