15 years from now Ravi's age will be 4 times his present age what is Ravi's present age​

Ravi’s present age will be 5.

Step-by-step explanation:

From the given, Let Ravi’s present age is taken as "a" years.  

After 15 years, his age = (a+15) years.  

By the given, it is identified that the age of Ravi after 15 years is equal to the 4 times of his present age.

Given,  

Then, it has been found that the present age of Ravi is 5 when his age after 15 years will be 4 times of his present age.  

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step-by-step explanation:

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85.560%

step-by-step explanation:

conditional probability is defined as:

p(a|b) = p(a∩b) / p(b)

in other words, the probability that a occurs, given that b has occurred = the probability that both a and b occur / the probability that b occurs.

in this example:

p(turns 64 | turns 44) = p(turns 64 & turns 44) / p(turns 44).

if someone turns 64, they must have already turned 44, so:

p(turns 64 | turns 44) = p(turns 64) / p(turns 44)

on page 42, we see that of the original 100,000, 94944 turn 44, and 81234 turn 64.   therefore:

p(turns 64 | turns 44) = 81234 / 94944

p(turns 64 | turns 44) = 0.85560