Builders have observed that residence windows are most attractive if they have the width to length ratio 3: 5. if a window is to be 48 inches wide, what should it's length be for the most attractive appearance?

Most attractive . . . width / length = 3:5 = 0.6

If width = 48 inches, then          48/length = 0.6

Multiply each side by 'length':    48 = 0.6 length

Divide each side by 0.6 :          length = 48/0.6 = 80 inches

When rates are expressed as a quantity of 1, such as 2 feet per second or 5 miles per hour, they are called unit rates. if you have a multiple-unit rate such as 120 students for every 3 buses, and want to find the single-unit rate, write a ratio equal to the multiple-unit rate with 1 as the second term.