Suppose that $60\%$ of the eighth graders and $30\%$ of the seventh graders at Washington Junior High participate in MATHCOUNTS. There are $150\%$ as many eighth-graders as there are seventh graders at the school. What percentage of the seventh and eighth graders, taken together, participates in MATHCOUNTS?

Igot 108 hope that’s right !

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.