How do you do a question like this? 80% as a fraction in simplest form.

Given abcd ac=38 and ae=3x+4 find the value of x

An office supply company conducted a survey before marketing a new paper shredder designed for home use. in the survey, 80 % of the people who tried the shredder were satisfied with it. because of this high satisfaction rate, the company decided to market the new shredder. assume that 80 % of all people are satisfied with this shredder. during a certain month, 100 customers bought this shredder. find the probability that of these 100 customers, the number who are satisfied is 69 or fewer.

What is the solution to the equation e3x=12? round your answer to the nearest hundredth