Which value of a below solves the equation: 3a +1=-a +3?
(1) -6
(2) 8
(3) -1
(4) 5

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.