novice12 wrote:

A circular jogging track forms the edge of a circular lake that has a diameter of 2 miles. Johanna walked once around the track at the average speed of 3 miles per hour. If t represents the number of hours it took Johanna to walk completely around the lake, which of the following is a correct statement?

A. 0.5< t < 0.75

B. 1.75< t < 2.0

C. 2.0 < t < 2.5

D. 2.5 < t < 3.0

E. 3 < t < 3.5

Diameter of circular lake \(= 2\) miles

Diameter \(= 2r\) ------- (\(r\) is the radius of circular lake)

Circumference of circular lake \(= 2\pi\)\(r\) \(= 2\pi\)

Average speed \(= 3\) miles/hour

\(Time (t)= \frac{distance}{speed} = \frac{Circumference}{speed} = \frac{2\pi}{3}\) ---------- (we can approximate value of \(\pi\) to \(3.1\))

Time \((t) = \frac{2*3.1}{3} = \frac{6.2}{3} = 2.0666\)

\(2.0666\) comes between \(2.0\) and \(2.5\). Therefore \(2.0 < t < 2.5\)

Answer (C)..._________________

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