Shana and Marie will update parts of their computer system. They will update the motherboard for $259.99,
2 USB ports for $39.95 each, and the DVD drive for $79.49.
Shana will save $12.50 per week and Marie will save
$15.50 per week. Which inequality can be used to find w,
the number of weeks it will take Shana and Marie to save
enough money for the parts?

17.08

correct me if i am wrong.

85.560%

step-by-step explanation:

conditional probability is defined as:

p(a|b) = p(a∩b) / p(b)

in other words, the probability that a occurs, given that b has occurred = the probability that both a and b occur / the probability that b occurs.

in this example:

p(turns 64 | turns 44) = p(turns 64 & turns 44) / p(turns 44).

if someone turns 64, they must have already turned 44, so:

p(turns 64 | turns 44) = p(turns 64) / p(turns 44)

on page 42, we see that of the original 100,000, 94944 turn 44, and 81234 turn 64.   therefore:

p(turns 64 | turns 44) = 81234 / 94944

p(turns 64 | turns 44) = 0.85560