Sum

The probability that a student X solves a problem in dynamics is `2/5` and the probability that student Y solves the same problem is `1/4`. What is the probability that the problem is solved

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#### Solution

Let event A: Student X solves the problem in dynamics,

event B: Student Y solves the problem in dynamics.

∴ P(A) = `2/5`, P(B) = `1/4`

∴ P(A') = 1 – P(A) = `1 - 2/5 = 3/5`

P(B') = 1 – P(B) = `1 - 1/4 = 3/4`

A and B are independent events,

A' and B' are also independent events

Let event D: Problem is solved.

Problems can be solved if at least one of the two students solves the problem.

∴ P(D) = P (at least one student solves the problem)

= 1 – P (no student solves the problem)

= 1 – P (A' ∩ B')

= 1 – P (A') P(B')

= `1 - 3/5 xx 3/4`

= `1 - 9/20`

= `11/20`

Concept: Independent Events

Is there an error in this question or solution?

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