A Recent Survey Shows That the Probability of a College

question 126

Multiple Choice

A recent survey shows that the probability of a college student drinking alcohol is 0.6. Further, given that the student is over 21 years old, the probability of drinking alcohol is 0.8. It is also known that 30% of the college students are over 21 years old. The probability of drinking or being over 21 years old is ________.

• A) 0.24.
• B) 0.42.
• C) 0.66.
• D) 0.90.

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Definitions:

Element

A substance consisting of atoms which all have the same number of protons, fundamentally the simplest substances that cannot be broken down using chemical methods.

Isotope

Variants of a particular chemical element that differ in neutron number, and consequently in nucleon number, but have the same number of protons.

Protons

Positively charged particles located in the nucleus of an atom, contributing to the atom's mass and charge.

Isotope

Atoms of the same element with the same number of protons but different numbers of neutrons, leading to different atomic masses.