If the area of the trapezoid is 78cm2 , the length of side a is 18cm and the height is 5cm, then find the length of b

Darcy deposited $390 into a savings account. as long as the account balance remains at or above $150, she does not have to pay a service fee for the account. for how many months can she withdraw $40 a month without having to pay service fees? a) 3 b) 5 c) 6 d) 9