SOLUTION: A commuter airplane travels 40 Km per hour faster than the television news helicopter over the city. The commuter airplane travels 1350km during the same time that the television n

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Question 896579: A commuter airplane travels 40 Km per hour faster than the television news helicopter over the city. The commuter airplane travels 1350km during the same time that the television news helicopter travels only 1050 km. How fast does the commuter airplane fly? How fast does the TV news helicopter fly?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let +t+ = time in hours
Let +s+ = speed of the T.N.H in km/hr
Equation for commuter airplane:
(1) +1350+=+%28+s+%2B+40+%29%2At+
Equation for television news helicopter:
(2) +1050+=+s%2At+
-------------------
(2) +t+=+1050%2Fs+
Substitute (2) into (1)
(1) +1350+=+%28+s+%2B+40+%29%2A%28+1050%2Fs+%29+
(1) +1350+=+1050+%2B+42000%2Fs+
(1) +300+=+42000%2Fs+
(1) +s+=+42000%2F300+
(1) +s+=+140+
----------------
The speed of the T.N.H is 140 km/hr
check:
(2) +t+=+1050%2Fs+
(2) +t+=+1050%2F140+
(2) +t+=+7.5+
(1) +1350+=+%28+s+%2B+40+%29%2A7.5+
(1) +1350+=+7.5s+%2B+300+
(1) +7.5s+=+1050+
(1) +s+=+140+
OK