In a carton of 10 eggs three were broken. Steven took 2 unbroken eggs and baked omelettes. A little later he took another egg out of the carton. What is the probability that this egg was not broken?

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.