Can someone please explain this to me?

Emma will roll two number cubes labeled 1 through 6. she will record the sum of the two numbers after each roll. she will roll the two cubes 540 times. how many times should emma expect the sum to equal 5?

Solve for n? [tex]z = \frac{3}{4} mn[/tex]

Identify the initial amount a and the growth factor b in the exponential function. a(x)=680*4.3^x