If P : Q : R = 9 : 10 : 11, then what is the value of (P + Q) : (Q + R) : (R + P)?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 19 : 21 : 20.
P : Q : R = 9 : 10 : 11
Let P = 9k, Q = 10k, and R = 11k, where k is a common factor.
Hence
(P + Q) : (Q + R) : (R + P) = (9k + 10k) : (10k + 11k) : (11k + 9k)
⇒ (P + Q) : (Q + R) : (R + P) = 19k : 21k : 20k
Since k is common to all terms,
so the ratio = 19 : 21 : 20