Determine whether these biconditionals are true or false. a.2 + 2 = 4 if and only if 1 + 1 = 2. b.1 + 1 = 2 if and only if 2 + 3 = 4.

A. is true because 2+2 does = 4 and  1 +1 =2
 B is false because 2 +3=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.