Bill sees two boxes of baseball cards at a card show. The first box has 150 cards for $12.55.The second box has 120 cards for $9.60. The cards in which box are cheaper?

D

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.