I really need help on this one

Use the normal approximation to the binomial distribution to answer this question. fifteen percent of all students at a large university are absent on mondays. if a random sample of 12 names is called on a monday, what is the probability that four students are absent?

Given f(x)= 9x+1 and g(x)=x^3, choose the expression (f*g)(x)

Awater tank holds 18000 gallons. how long will it take for the water level to reach 6000 gallons if the water is used at anaverage rate of 450 gallons per day