The probability that none of the four have been vaccinated is
(1-0.63)^4 = 0.01874161
The probability that at least one has been vaccinated is the complement of this,
≈0.9813
it is 2.981580515 are you a boy or not
$27.79. First multiply the percentage as a decimal out of 100. Subtract that number from the original amount. Do the same thing with the number you got from subtracting(multiply by percentage then subtract from starting amount(the new one)) you end up with $27.79