GATE CS 2020 QGA-7 — General Aptitude

The letters $P, Q, R, S, T$ are consecutive letters in the English alphabet. Let us observe the pattern of their corresponding numerical values:

• $P = 3 = 3^1$
• $R = 27 = 3^3$
• $T = 243 = 3^5$

The values form a geometric progression with a base of $3$ and exponents increasing by $1$ for each consecutive letter:

• $P = 3^1 = 3$
• $Q = 3^2 = 9$
• $R = 3^3 = 27$
• $S = 3^4 = 81$
• $T = 3^5 = 243$

We need to find the value of $Q + S$:

Hence, the correct option is C.