I need help on dis question

Carl's candies has determined that a candy bar measuring 3 inches long has a z-score of +1 and a candy bar measuring 3.75 inches long has a z-score of +2. what is the standard deviation of the length of candy bars produced at carl's candies?

Y= 4x + 3 y = - 1 4 x - 5 what is the best description for the lines represented by the equations?

According to the general equation for conditional probability if p(anb)=3/7 and p(b)=7/8 what is p(a i b)