SOLUTION: An airplane flew for 8 hours at an airspeed of x miles per hour (mph),and for 7 more hours at 325 mph.If the average for the entire flight was 350 mph, which equations could be us

Algebra ->  Equations -> SOLUTION: An airplane flew for 8 hours at an airspeed of x miles per hour (mph),and for 7 more hours at 325 mph.If the average for the entire flight was 350 mph, which equations could be us      Log On


   

Question 265578: An airplane flew for 8 hours at an airspeed of x miles per hour (mph),and for 7 more hours at 325 mph.If the average for the entire flight was 350 mph, which equations could be used to find x?
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
D=RT
D=8X
D=7*325
(8X+7*325)/15=350
(8X+2,275)/15=350 CROSS MULTIPLY
8X+2,275=15*350
8X+2,275=5,250
8X=5,250-2,275
8X=2,975
X=2,975/8
X=371.875 MPH. FOR THE 8 HOUR LEG.
2,975+2,275=5,250 IS THE TOTAL DISTANCE
5,250=R(8+7)
5,250=15R
R=5,250/15
R=350 MPH. IS THE AVERAGE SPEED.