Suppose you have two quantitative independent variables, x1 and x2, that you want to use to predict y. Which of the following terms would you add to the model if you believe the relationship between y and x1 depends on the value of x2? a. x1x2
b. x22
c. x13
d. x12

what are ur choices?

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.