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GATE 2022 IN – Question 7

General Aptitude · Quantitative Aptitude: Arithmetic and Number Computation · 2 marks · Multiple choice

A game consists of spinning an arrow around a stationary disk as shown. At rest it has eight equally likely outcomes: sectors numbered 1 through 8. Two such disks have independently spun arrows. What is the probability that the sum of the resulting numbers is 8?

Diagram for GATE 2022 IN question 7
  1. $1/16$
  2. $5/64$
  3. $3/32$
  4. $7/64$

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Correct answer: (D) $7/64$

Explanation

Independent eight-outcome disks give 64 equally likely ordered pairs. Favorable pairs are (1,7),(2,6),…,(7,1): seven pairs. Probability is **7/64, D**.