Bunuel wrote:

If the average (arithmetic mean) life expectancy amongst males in country X is 68 years while the life expectancy of females is 72 years, what is the average life expectancy for the entire population?

(1) The ratio of males to females is 14 : 17.

(2) The number of females exceeds the number of males by one million.

Lets say number of males in country X = M and number of females in country X = F. So total life of males = 68*M, and total life of females = 72*F. Average life expectancy = (Total life)/(total number of people) = (68M + 72F)/(M+F)

(1) Ratio of males to females = M:F = 14:17. We can put M=14k and F=17k in the formula to get the answer.

Average life expectancy = (68*14k + 72*17k)/(14k + 17k). 'k' will be eliminated and we will get the answer.

Sufficient.

(2) F = M + 1000000.

Average life expectancy = [68M + 72(M+100000)]/[M+M+1000000]. This cannot be determined until we know the value of M. So

Insufficient.

Hence

A answer