Prove the following statements about sets (a) if a and b are sets and if a c b, then a u b-b and a n b = a. (b) anb aub.

if you explain the the question more correctly i might be able to answer this better

step-by-step explanation:

4 + 5 7/9= 9 7/9

step-by-step explanation:

answer is x<

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.