There are 4 blood types, and not all are equally likely to be in blood banks. In a certain blood bank, 49% of donations are Type O blood, 27% of donations are Type A blood, 20% of donations are Type B blood, and 4% of
donations are Type AB blood. What is the expected number of donations until the first Type AB donation is
received?
02.127
4
O24.495
25

Can any one me with the answers to these questions asap?

Mozart lenses inc. recently introduced seelites, a thinner lens for eyelasses. of a sample of 800 eyeglass wearers, 246 said they would purchases their next pair of eyeglasses with the new lenses. lenses inc. estimates that the number of people who purchase eyeglasses in a year is 1,700,000. most eyeglasses wearer buy one new pair of eyeglasses a year. what is the annual sales potential for the new lenses.

Afamily has five members. a mom, a dad, two sisters, & a brother. the family lines up single file. what is the probabillity that the mom is at the front of the line