A speed of an athelete who completes two thirds of a circular track of radius 350 metres in 5 minutes is ?

Distance of full circular track is (2x350xpi) metres.

So distance covered in 5 mins is (2x350xpix2/3) metres.

So speed is [(2x350x2/3xpi)/5] m/min

or (2x70x2/3xpi) m/min (dividing 350 by 5)

or [(2x70x2/3xpi)/60] m/sec, there being 60 seconds in a minute.

That's the theory.

I'll leave you to do the arithmetic.

you know the radius of the track

so you can calculate its circumference

so you can calculate 2/3 of that

this is the distance travelled

speed = distance/time

(and it you couldnt work out how to do this question you really MUST go back and study your notes or books cos you are gonna get your a//se kicked on monday)