The greatest common factor (GCF) is the greatest factor that divides two integers.

A rational number (or fraction) is represented as a ratio between two integers, a and b, and has the form \({a \over b}\) where a is the numerator and b is the denominator. An improper fraction (\({5 \over 3} \)) has a numerator with a greater absolute value than the denominator and can be converted into a mixed number (\(1 {2 \over 3} \)) which has a whole number part and a fractional part.

Average speed in miles per hour is the number of miles traveled divided by the number of hours:

Solving for distance:

distance = \( \text{speed} \times \text{time} \)
distance = \( 50mph \times 3h \)
150 miles

To add these fractions, first find the lowest common multiple of their denominators. The first few multiples of 2 are [2, 4, 6, 8, 10, 12, 14, 16, 18, 20] and the first few multiples of 4 are [4, 8, 12, 16, 20, 24, 28, 32, 36, 40]. The first few multiples they share are [4, 8, 12, 16, 20] making 4 the smallest multiple 2 and 4 share.

Next, convert the fractions so each denominator equals the lowest common multiple:

\( \frac{6 x 2}{2 x 2} \) + \( \frac{8 x 1}{4 x 1} \)

\( \frac{12}{4} \) + \( \frac{8}{4} \)

Now, because the fractions share a common denominator, you can add them:

\( \frac{12 + 8}{4} \) = \( \frac{20}{4} \) = 5

To fill a 8 gallon tank exactly halfway you'll need 4 gallons of fuel. Each fuel can holds 2 gallons so:

cans = \( \frac{4 \text{ gallons}}{2 \text{ gallons}} \) = 2