At summer camp, the campers pick two activities for the first day of camp. they can choose from among hiking, canoeing, rock climbing, and bird watching. how many different combinations of activities are there?

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.