Question

The inner circumference of a circular track is 880m and track is 28m wide calculate cost of levelling the track at the 50paise per sq.m

Answer 1

inner circumference=880m
2πr=880
r= 880*7/22*2
r=140 m
radius of outer circle= R =28+ 140= 168 m.

Area of track = area of outer circle
-Area of inner circle
=π(R²-r²)
=22/7{ (168)² -(140)²}
=22/7(28224-19600)
=22/7(8624)
=27104m²

then the cost of lavelling = Rs.0.5*27104m²
=Rs 13552.0