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Jane is running on a circular track with a radius of 50 yards. A mile is 1760 yards. What is the least number of complete laps she must run to cover a distance of at least 4 miles?​

Respuesta :

Jane needs to run 22 laps to cover 4 miles

Solution:

From given question,

Jane is running on a circular track with a radius of 50 yards

Radius = 50 yards

The total distance covered in 1 lap is equal to circumference of circular track

The circumference of circle is given as:

[tex]C = 2 \pi r[/tex]

Where, "C" is the circumference and "r" is the radius

[tex]C = 2 \times 3.14 \times 50 = 314[/tex]

Thus one lap is equal to 314 yards

Convert yards to miles

Given that,

1 mile = 1760 yards

[tex]1 \text{ yard } = \frac{1}{1760} \text{ miles }[/tex]

Therefore, 314 yards is equal to,

[tex]314 \text{ yards } = \frac{1}{1760} \times 314 \text{ miles } = 0.1784 \text{ miles }[/tex]

What is the least number of complete laps she must run to cover a distance of at least 4 miles?​

In 1 lap, she covers 0.1784 miles

Let "x" be the number of laps needed to cover 4 miles

Therefore,

1 lap = 0.1784 miles

x lap = 4 miles

This forms a proportion and we can solve the sum by cross multiplying

[tex]4 \times 1 = x \times 0.1784\\\\x = \frac{4}{0.1784}\\\\x = 22.42 \approx 22[/tex]

Thus she needs to run 22 laps to cover 4 miles

18

Step-by-step explanation:

Half of 4 times 9=18

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