Can someone help?

Aclass consists of 55% boys and 45% girls. it is observed that 25% of the class are boys and scored an a on the test, and 35% of the class are girls and scored an a on the test. if a student is chosen at random and is found to be a girl, the probability that the student scored an ais

When x = 3 and y = 5, by how much does the value of 3x2 – 2y exceed the value of 2x2 – 3y ?

Find an bif a = {3, 6, 9, 12) and b = {2, 4, 6, 8, 10).