Agambler bets ten times on events of probability \(1/10\), then twenty times on events with probability \(1/20\), then thirty times on events with probability \(1/30\), then forty times on events with probability \(1/40\). Assuming the vents are independent, what is the approximate distribution of the number of times the gambler wins ? (use Poisson approx. of binomial)

[Pitman 2.5, pg 227]