A takem powder manufacturing company lad launched a now type of advertisement. The eompany estimated that a person who comes across their advertisement will buy their product with a probability of $0,7$ and these who do not see the advertisement will buy the prixduct with a probability of $0\mathrm{.}3.$ If in an area of $1000$ people, $70\%$ had come across the advertivement, find the probability that a person who buys the prodict

$($a$)$ has not come across the advertisement and.

$($b$)$ has come across the advertisement?

Answer: $9/58,49/58$