Question

Two planes move along a circle of circumference 1.2 km with constant speeds. When they move in different directions, they meet every 15 seconds and when they move in the same direction, one plane overtakes the other every 60 seconds. Find the speed of the slower plane. A.0.04 km/s B.0.03 km/s C.0.05 km/s D.0.02 km/s

Answer 1

Answer:

0.03 km/s

Step-by-step explanation:

Given  

Two planes move along a circle of circumference 1.2 km with constant speeds. When they move in different directions, they meet every 15 seconds and  when they move in the same direction, one plane overtakes the other every 60 seconds. Find the speed of the slower plane. A.0.04 km/s B.0.03 km/s C.0.05 km/s D.0.02 km/s

Let their speeds be x m/s and y m/s.

So 1200 / x + y = 15

x + y = 1200 / 15

x + y = 80 --------------1

Also 1200 / x – y = 60

x – y = 1200 / 60

x – y = 20---------------2

From 1 and 2 we get

x + y = 80

x – y = 20

2x = 100

x = 50 m/s

50 + y = 80

y = 80 – 50

y = 30 m/s

So y = 30 x 1/1000  

y = 0.03 km / s