Please help! Correct answer only please! Mike recently increased the size of his truck tires from 26.16 inches to 28.95 inches. If mike didn't re-calibrate his speedometer, how fast is he really going on the new tires when his speedometer shows he is traveling 60 mph?

Group of answer choices

A. 54.2 mph

B. 63.8 mph

C. 66.4 mph

D. 69.7 mph

C. 66.4 mph

Step-by-step explanation:

∵ The ratio of speed of motorcycle and the circumference of the tyre is constant for a motorcycle,

If x be the speed ( in mph ) of a motorcycle having the tyre of diameter 28 inches,

⇒ The ratio of speed and circumference = \frac{x}{2\pi (14)}

( Because radius = Diameter / 2 ),

While, the speed of the same motorcycle having the tyre of diameter 25 inches is 60 mph,

⇒ The ratio of speed and circumference = \frac{60}{2\pi (12.5)}

By the above statement,

\frac{x}{2\pi (14)}=\frac{60}{2\pi (12.5)}

\implies x=\frac{60\times 14}{12.5}=\frac{336}{5}=67.2\approx 67

So, the actual speed of the motorcycle after changing the tyre is 67 mph ( approx )

Hence, option 'C' is correct.

Step-by-step explanation: