Example 11* (Optional) A missing helicopter is reported to have crashed somewhere in the rectangular region shown in Fig. 15.2. What is the probability that it crashed inside the lake shown in the figure
Here, we use area to find probability
First,
let us find length and height of the lake
Length of lake = 9 – 6 = 3 km
Breadth of lake = 4.5 – 2 = 2.5 km
Now,
Area of lake = 3 km × 2.5 km
Total Area = 4.5 km × 9 km
Now,
P (helicopter will fall in lake)
= (𝐴𝑟𝑒𝑎 𝑜𝑓 𝑙𝑎𝑘𝑒)/(𝑇𝑜𝑡𝑎𝑙 𝐴𝑟𝑒𝑎)
= (3 × 2.5)/(4.5 × 9)
= (𝟑 × 𝟐𝟓)/(𝟒𝟓 × 𝟗)
= (1 × 25)/(45 × 3)
= (1 × 5)/(9 × 3)
= 5/27
So, Probability is 𝟓/𝟐𝟕

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Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.