The inner circumference of a circle race track 18 m wide is 880 m. Find the radius of the outer circle. Choose the correct choice:
A) 120m	B) 145m	C) 130m	D) 140m	E) 122m
Let inner radius be r metres   Then 2πr = 640   2 × 22/7 r = 880   44/7 r = 880   r = 880 × 7/44 = 140 m   Answer is 140m.
<result>D</result>
The inner circumference of a circle race track 18 m wide is 880 m. Find the radius of the outer circle.