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GATE 2022 CY – 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 below. When the arrow comes to rest, there are eight equally likely outcomes. It could come to rest in any one of the sectors numbered 1, 2, 3, 4, 5, 6, 7 or 8 as shown. Two such disks are used in a game where their arrows are independently spun. What is the probability that the sum of the numbers on the resulting sectors upon spinning the two disks is equal to 8 after the arrows come to rest?

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

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Show answer and explanation

Correct answer: (D) $7/64$

Explanation

The 64 ordered outcomes are equally likely. Favourable pairs are(1,7),(2,6),(3,5),(4,4),(5,3),(6,2),(7,1): seven outcomes.

Thus probability is **7/64, D**; there is no(0,8) outcome because the minimum number is 1.