If a: b = c : d then (ma + nc): (mb + nd) is equal to:

Here, a: b = c : d,

Put a = c and b = d in the eq., we get

⇒ (ma + nc) : (mb + nd) = (mc + nc) : (md + nd)

                                     = c (m + n) : d (m + n)

                                     = c : d or \(\frac{c}{d}\)