As an estimate, we are told that 5 miles is equal to 8 km. Convert 68 km to miles?
The correct answer and explanation is:
To convert 68 kilometers to miles using the estimate that 5 miles is approximately equal to 8 kilometers, start by setting up a ratio based on the given equivalence.
Since 5 miles ≈ 8 kilometers, this means that 1 mile is approximately equal to 8 ÷ 5 kilometers, or 1.6 kilometers. Conversely, 1 kilometer is approximately equal to 5 ÷ 8 miles, which is 0.625 miles.
To find how many miles are in 68 kilometers, multiply 68 kilometers by 0.625 miles per kilometer:
68 km × 0.625 miles/km = 42.5 miles
So, 68 kilometers is approximately 42.5 miles using this estimation.
The process involves understanding that converting between two units requires knowing the relationship or ratio between those units. Since the problem provides a conversion factor of 5 miles to 8 kilometers, this ratio allows converting in either direction by adjusting the fraction accordingly.
By converting from kilometers to miles, dividing the kilometer value by the factor that relates the two units is necessary. The ratio 5 miles per 8 kilometers means one kilometer is 5/8 of a mile. Multiplying the distance in kilometers by 5/8 converts it into miles.
This estimation method is useful when high precision is not required, and an approximate conversion suffices. The actual precise conversion uses 1 mile equal to 1.60934 kilometers, which would give a slightly different result. But for everyday purposes, the simplified ratio 5 miles to 8 kilometers offers a convenient and quick way to convert distances.
In summary, the key steps are recognizing the ratio, converting the units by multiplication, and applying this to the given value. Using 5 miles ≈ 8 kilometers, 68 kilometers converts to about 42.5 miles. This method helps easily estimate distances between the two measurement systems.