SOLUTION: Maria drove for two hours to get to the Fort William airport. She then flew from Fort William to Green Island. During the four hour flight to Green Island, the average speed of the

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Question 1151331: Maria drove for two hours to get to the Fort William airport. She then flew from Fort William to Green Island. During the four hour flight to Green Island, the average speed of the plane was three times the average speed that Maria traveled on the drive to the airport. If Maria traveled a total distance of 1120 km, what was the average speed o each part of her trip.
Found 2 solutions by josmiceli, ikleyn:
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +s+ = her ave speed driving
+3s+ = her ave speed flying
Let +d+ = distance in km that she drove
+1120+-+d+ = distance in km she flew
------------------------------------------------
Equation for driving:
(1) +d+=+s%2A2+
Equation for flying:
(2) +1120+-+d+=+3s%2A4+
------------------------------
Plug (1) into (2)
(2) +1120+-+2s+=+12s+
(2) +14s+=+1120+
(2) +s+=+80+
and
+3s+=+240+
----------------------
She drove at 80 km/hr
She flew at 240 km/hr
-----------------------------
check:
(1) +d+=+s%2A2+
(1) +d+=+80%2A2+
(1) +d+=+160+
and
(2) +1120+-+d+=+3s%2A4+
(2) +d+=+1120+-+12s+
(2) +d+=+1120+-+960+
(2) +d+=+160+
OK

Answer by ikleyn(52794) About Me  (Show Source):
You can put this solution on YOUR website!
.

Let x be the average speed driving, im km/h.


Then the average speed flying is 3x, according to the condition.


Also, from the condition, you have this equation for the total distance in both sides of the equality sign


    2x + 4*(3x) = 1120  kilometers.


It implies


    2x + 12x = 1120

    14x      = 1120

      x      = 1120/14 = 80.


ANSWER.  The average speed is 80 km/h driving and 3*80 = 240 km/h flying.

Solved.