Step-by-step explanation: You only need a common denominator when adding or subtracting, but you do not need a common denominator when multiplying or dividing.
11/4 - 3/8 --- GIVEN
22/8 - 3/8 --- Both now have the same common denominator. Since, 3/8's is already done, you just have to change 11/4 by multiplying both 11 & 4 by 2 to get the same denominator which is 8
So first you would multiply $6.50 by 4.5 and you get 29.25, so that represents how much she would make in one day! Then multiply 5 days a week by 6 weeks and you get 30 then multiply $29.25 by 30 to get the total!