The inner circumference of a circle race track 18 m wide is 880 m. Find the radius of the outer circle. Choose the correct option
A) 120 m
B) 145 m
C) 130 m
D) 140 m
E) 122 m

Rationale: let inner radius be r metres then 2 π r = 640 2 × 22 / 7 r = 880 44 / 7 r = 880 r = 880 × 7 / 44 = 140 m answer is d .
Answer: D