DAY 48

Comment

This item involves conditional probabilities, but it can be solved by thinking yourself into the situation:
Cara very often burns the toast when she oversleeps but she oversleeps very, very rarely. She sometimes burns the toast when she doesn't oversleep ... .

Answer

The probability that Cara burns the toast tomorrow is less than evens.

Readers' methods

Lester Gould, NYC:
The probability that Cara burns the toast when she does not oversleep is 3/10, which is quite a lot less than evens.
So I think the probability that she burns the toast tomorrow is less than evens, even when you include the possibility that she oversleeps, because she hardly ever oversleeps.

Adrian T, LE11:
P(burning toast) = (1/20 x 9/10) + (19/20 x 3/10) = 33/100,
ie there is a 33 % chance of her burning the toast tomorrow.