renjana wrote:

A hiking club’s trip will be cancelled if, on the first day of the trip, the temperature is less than 20 degrees Fahrenheit or it is snowing. If there is a 15% chance that temperatures will be below 20 degrees and a 60% chance that it will not snow, what is the likelihood that the trip will be cancelled?

A. 40%

B. 49%

C. 55%

D. 66%

E. 75%

P(Trip cancelled )= P(Temp less than 20) +(OR) P(Snowing)

(P(Temp less than 20) = 15/100

P(Snowing) = 40/100

P(Trip cancelled )= 55/100

Please correct me if i am wrong !

The question is looking for the likelihood in which the trip will be canceled.

A: Temp less than 20 =

15%B: Snowing =

40%not A: Temp not less than 20 =

85%not B: Not Snowing =

60%The occurrence of A & B are parallel and Happening of

either of them will cancel the trip.

The trip is going to be canceled under the following conditions:

A*B + A*(not B) + (not A)*B :

15% * 40% + 15% * 60% + 85% * 40% = 49%

Shortcut method: Find the probability in which trip will happen and subtract from the total set of events, i.e.,

1 - (when trip won't be canceled) : 1 - (not A)*(not B)

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