Landon owns a small business selling clothing. He knows that in the last week 58 customers paid cash, 61 customers used a debit card, and 13 customers used a credit card. Based on these results, express the probability that the next customer will pay with a credit card as a fraction in simplest form.

let x and 400 - x be the two numbers.  

==> 0.80x + 0.85(400 - x) = 400 - 68 from the statement of the problem.  

< ==> 0.80x + 0.85(400 - x) = 400 - 68  

==> 340 - 0.05x = 332  

< ==> -0.05x = -8 ==> x = 160, the first number ==> 400 - x = 240, the second number.

he has 140 chickens because he has 10 times more chickens than ducks and he has 14 ducks so 14*10=140