If a : b = c : d then, (ma + nc) / (mb + nd) is equal to? m : n na : mb a : b md

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Question
If a : b = c : d then, (ma + nc) / (mb + nd) is equal to?
Options
A. m : n
B. na : mb
C. a : b
D. md : nc

Correct Answer

a : b

Explanation

Let (a/b) = (c/d) = k
Then, a = bk and c = dk.
? (ma + nc) / (mb + nd) = (mbk + ndk) / (mb + nd) = k(mb + nd/mb + nd)
= k = a/b = a : b.

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2.
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Options
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