JAMB - Mathematics (2007 - No. 6)
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?
27/40
17/20
3/30
33/40
คำอธิบาย
P(At least 11 yrs) = P(11yrs) + P(12yrs)
= \(\frac{27}{40}\) + \(\frac{7}{40}\)
= \(\frac{34}{40}\)
= \(\frac{17}{20}\)
= \(\frac{27}{40}\) + \(\frac{7}{40}\)
= \(\frac{34}{40}\)
= \(\frac{17}{20}\)