When it reads "the quotient of 3 more than a number and 5" it is separated as follows: "the quotient of [3 more than a number] and [5]" Therefore Quantity 1 is 3 more than a number and Quantity 2 is 5.
You can replace "a number" with a variable (they want you to use n in this case): 3 more than n Which is the same as saying: 3 + n