Question

the probability that a person A who is now 25 years old, lives for another 30 years is 2/5, and the probability that the person B who is now 45 years old lives for another 30 years is 7/16, find the probability that at least one of these person will be alive. # 0 years hence. plz ,plz plz answer. ​

Answer 1

Given:  Probability that a person A who is now 25 years old, lives for another 30 years is 2/5,  the probability that the person B who is now 45 years old lives for another 30 years is 7/16.

To find: Find the probability that at least one of these person will be alive

Solution:

• Let a person A who is now 25 years old, lives for another 30 years be A.

               So, p(A) = 2/5

• Let  the person B who is now 45 years old lives for another 30 years be B.

               So, p(B) = 7/16

• Now, probability of A to die: 1-2/5 = 3/5 ............p(C)

• Similarly, probability of A to die: 1-7/16 = 9/16..............p(D)

• Probability that at least one of these person will be alive:

                p(A) X p(D) + p(B) X p(C)

                (2/5 X 9/16) + (7/16 X 3/5)

                18/80 + 21/80

                39/80

Answer:

                     The probability that at least one of these person will be alive is 39/80.