Answer:
$9426.50
Step-by-step explanation:
let noel's salary = x, robert's salary = y and john's salary = z
y = x - 512.75 ..........(1)
z = 3y = 3(x - 512.75) = 3x - 1538.25 ...............(2)
x + y + z = 47645.25..........................(3)
substitute for y and z
x + (x - 512.75) + (3x - 1538.25) = 47645.25
x + x - 512.75 + 3x - 1538.25 = 47645.25
5x = 47645.75 + 512.75 + 1538.25
5x = 49696.25
divide both sides by 5
x = 9939.25 ..... noel's salary
to get robert's salary substitute x in equation 1
y = 9939.25 - 512.75 = 9426.50
y = $9426.50..... robert's salary