Help me please this is my last question

339.3 mi^2

Step-by-step explanation:

The formula for the surface area of a cylinder: 2pi*rh + 2pi*r^2

substitute the radius and height into this formula, and remember that radius is half of the diameter.

A is the correct answer. Hope this helps and have a great day!!

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.