I took the quiz and this what the answer, I hope this help future people that had the same question.
Let the cost of one cup of hot chocolate be = x
Let the cost of one cup of hot tea be = y
Paul paid $ 25.50 for 3 cups of hot chocolate and 4 cups of tea.
Equation becomes =
...(1)
As given, the cost of each cup of tea was 2/3 the cost of each cup of hot chocolate.
.... (2)
Putting the value of y from (2) in (1)

=
=
=
x=4.5

=
y =3
Hence each cup of hot chocolate is $4.50
Each cup of tea is $3.
I believe the answer should be 6x+3
The integer you’re looking for is 3