Question

the inner circumference of a circular track is 220 m.the track is 7m wide everywhere.calculate the cost of putting up a fence along the outer circle at the rate of rupee 2 per meter.plz solve this question

Answer 1

inner circumference = 220

2 π r = 220

r *2* 22 = 220 * 7

r = 35 m [ inner radius ]

inner radius , r₁ = 35 m
outer radius , r₂ = 35 + 7 = 42 m

outer circumference = 2 π r ₂

= 2 * ( 22 / 7 ) * 42 = 264 m

Cost of fencing = Rs 2 * 264 = Rs 528

Answer 2

Answer:

Circumference of inner side = 220m

⇒2πr=220⇒r=

44

220×7

​

=35m

Now, width of track =7m

∴ Outer radius =35+7=42m

Therefore outer circumference =2πR=2×

7

22

​

×42=264m

∴ Cost of fencing = Rs. (264×2) = Rs. 528