Question
A bag contains 7 white balls, 5 black balls, and 4
orange balls. Two balls are drawn at random. Find the probability that the two balls are white.Solution
Number of ways of selecting two white balls = 7 Câ‚‚
Total number of balls = 7 + 5 + 4 = 16
Number of ways of selecting two balls = 16 Câ‚‚
Probability = 7 C₂ ÷ 16 C₂ = (7 × 6) ÷ (16 × 15) = 42 ÷ 240 = 7/20
More Probability Questions
A system is in a safe state when:
What is a table joined with itself called?
Which type of join returns rows when there is a match in both tables?
What is context switching?
Indexing in DBMS improves:
Which isolation level allows dirty reads?
Which operation is NOT part of relational algebra?
Shadow paging in recovery eliminates the need for:
Distributed transactions typically use which protocol for atomicity?
Which concurrency anomaly is specific to phantom reads?
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