Question

If P, Q, R are physical quantities, having different dimensions, which of the following combinations can never be a meaningful quantity?
(a) (P – Q)/R
(b) PQ – R
(c) PQ/R
(d) (PR – Q^2)/R
(e) (R + Q)/P

Answer 1

a and e can never be possible as there dimensions are different and can never be added or subtracted directly. In other P,Q and R are in multiplication which may be the possible case.