Question
A person throws a biased coin on which head appears in 30%
of situations. If the person gets Rs. 20 for each tail and loses Rs. 30 for each head, then find the average amount lost or gained by him per toss.Solution
Let, number of times the coin was tossed be ‘x’
Probability of getting head = 0.3
Probability of getting tail = 0.7
Number of times of getting head = 0.3x
Number of times of getting tail = 0.7x
Required average amount lost per toss = (0.7x × 20 – 0.3x × 30)/x
= (14x – 9x)/x
= 5x/x = Rs. 5 gain
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