Equivalent ratio to 21/126

Airline passengers arrive randomly and independently at the passenger-screening facility at a major international airport. the mean arrival rate is 10 passengers per minutes. compute the following probabilities. p(x = 4) p(x > 11)

Simplify (a/b - b/a) times (a - a^2/a+b) a - a^2/a=b is a mixed number

Simplify the expression and find the missing terms. the simplest form of has in the numerator and in the denominator.