Problem Solving

Refer to the following prompt for the questions 1-2:

The bear alarm at Grizzly's Peak ski resort sounds an average of once every thirty days, but the alarm is so sensitively calibrated that it sounds an average of ten false alarms for every undetected bear. Despite this, the alarm only sounds for three out of four bears that actually appear at the resort.

1. If the alarm were to sound an average of ten false alarms for every detected bear, the probability that a sounded alarm would indicate an actual bear would
(A) Decrease by approximately 75%
(B) Decrease by approximately 33%
(C) Decrease by approximately 14%
(D) Increase by approximately 33%
(E) Increase by approximately 75%


2. Approximately how many bears appear at the resort every year?
(A) 1
(B) 3
(C) 4
(D) 10
(E) 13

Please provide explanation of your answer so as to help other members.

Source: Veritas Prep

[spoiler]OA: After some discussions[/spoiler]

Two more questions in the sequel and with the same prompt: https://www.beatthegmat.com/the-bear-ala ... 62997.html