Together, Andrea and Brian weight p pounds. Brian weights 10 pounds more than Andrea. Brain and Andrea’s dog, Cubby, weights p/4 pounds more than Andrea. In terms of p, what is Cubby’s weight in pounds?

since "Brian and Cubby" form a plural noun and require a plural verb.

So, now that we know how to interpret the question, our equations are:

A + B = P

B = A + 10

C = A + P/4

We want to solve for C, so let's get rid of A and B by getting A in terms of P and then subbing into the Cubby equation:

A + 10 = B

A + A + 10 = P

2A = P - 10

A = P/2 - 5

C = P/2 - 5 + P/4

C = (2P/4) + P/4 - 5

C = (2P + P)/4 - 5

C = 3P/4 - 5