Question

The radius of track A is 14 m. If the initial separation between Ted and Ned is 22 m, find the radius of track B.

• A. 16 m
• B. 16.5 m
• C. 17 m
• D. 17.5 m

Answer 1

The correct option is D

17.5 m

The circumference of track A = 2 $\pi$ r = 2 $\times$ (22/7) $\times$ 14 = 88 m

The circumference of track B = circumference of track A + 22 m = (88 + 22) m = 110 m

Let the radius of track B be r’. So, circumference of track B = 2 $\pi$ r’

2 $\pi$ r’ = 110 m

2 $\times$ (22/7) $\times$ r’ = 110

r’ = 17.5 m