HELP ME PLEASE! ALGEBRA.

Let's assume that since 49% of the adults in the city are males, then the rest of the population (which is 51%) are females. This means that 51 adults out of 100 (hypothetically) are females. Since the percentage of adult females who rent action-movie DVDs is 10% and there are 51 females in the city, then it should come at a ratio of 10/51. 

Thus, the answer is that the probability of an adult female who rents action-movie DVD getting picked in the sample is .1961 or .20 (that's 20%) of the whole population in the city.