I want to make a sweater where the pattern says I need 2800 meters of yarn. The yam that I want to use comes in skeins that average 300 meters each. The standard deviation is 100 meters. I bought 9 skorts and I think it should be enough.

What is the probability that I will have enough yarn?

Hint: the formulis in the Central Limit Theorem for normal distributions with mean and standard deviation or is

F(2) = P {