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\(\begin{array}{c|c} \text{Age in years} & 10 & 11 &...

Age in years101112Number of pupils6277
The table above shows the number of pupils in each age group in a class. What is the probability that a pupil chosen at random is at least 11 years old?

A.

2740

B.

1720

C.

3340

D.

320

Correct answer is B

Total number of pupils = 7 + 27 + 6 = 40

n(at least 11 years old) = 27 + 7 = 34.

P(picking a pupil who is at least 11 years old) = 3440=1720.