Part 4 of helping my friend 6th grade math btw also help me on pt 3 of helping my friend plz show u work thx my fearless mysterious

Determine the mean and variance of the random variable with the following probability mass function. f(x)=( 729divided by 91) (1 divided by 9) superscript x baseline comma x equals 1,2,3 round your answers to three decimal places (e.g. 98.765).

If olu is twice as old as funmi if the sum of their ages is 60 how old is olu

What is the similarity ratio of a cube with volume 729m^3 to a cube with volume 3375 m^3