SOLUTION: aeroplane left 30min. later than its scheduled time and in order to reach distination 1500km away in time, it has to increase its speed by 250km/hr from its usual speed. determine

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Question 1014720: aeroplane left 30min. later than its scheduled time and in order to reach distination 1500km away in time, it has to increase its speed by 250km/hr from its usual speed. determine its usual speed.
Found 2 solutions by josgarithmetic, MathTherapy:
Answer by josgarithmetic(39614) (Show Source):
You can put this solution on YOUR website!
r, usual speed
t, usual time
Basic travel rates rule, RT=D

speed time distance Usual r t 1500 Late r+250 t-1/2 1500

Do you know what to do with this?

Answer by MathTherapy(10549) (Show Source):
You can put this solution on YOUR website!
aeroplane left 30min. later than its scheduled time and in order to reach distination 1500km away in time, it has to increase its speed by 250km/hr from its usual speed. determine its usual speed.

Let usual speed be S
Then time it usually takes is:
After increasing its speed, new speed becomes: S + 250
Time taken at increased speed:
We now get:
Solve for S, or regular speed to get: km/h