Reniel is 13 years old. He is two years younger than his brother, Gelo. If Gelo is five times older than their sister, how old is their sister?

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25

Arandom sample of n = 25 observations is taken from a n(µ, σ ) population. a 95% confidence interval for µ was calculated to be (42.16, 57.84). the researcher feels that this interval is too wide. you want to reduce the interval to a width at most 12 units. a) for a confidence level of 95%, calculate the smallest sample size needed. b) for a sample size fixed at n = 25, calculate the largest confidence level 100(1 − α)% needed.

Ahummingbird lives in a nest that is 15 feet high in a tree.the hummingbird flies 17 feet to get from its nest to a flower on the ground.how far is the flower from the base of the tree?