Question

The probability of a student getting an A....

Answer 1

`P (M\ and\ C) = (1)/(4)=25\%`

Explanation:

We call M the event in which a student gets an A in math and we call C the event in which a student gets an A in chemistry. As the events are not mutually exclusive, then.

`P (M\ or\ C) = P (M) + P (C) - P (M\ and\ C)`

In this case we know that:

`P (M\ or\ C) = (7)/(10)`

`P (M) =(17)/(20)`

`P (C) =(1)/(10)`

So

`P (M\ and\ C) = P (M) + P (C) - P (M\ or\ C)`

`P (M\ and\ C) = (17)/(20) + (1)/(10) -(7)/(10)`

`P (M\ and\ C) = (1)/(4)`