40+3+.04+.003
expanded form is showing what you have to add together
A1 = 4
a2 = 5a1 = 5 x 4 = 20
a3 = 5a2 = 5 x 20 = 100
a4 = 5a3 = 5 x 100 = 500
a5 = 5a4 = 5 x 500 = 2,500
Tn = ar^(n-1); where a = 4, r = 5
Tn = 4(5)^(n-1) = 4/5 (5)^n
Explicit formular is Tn = 4/5 (5)^n
Recursive formular is
Write and solve an equation of ratios:
$6,800 x
------------- = --------------
144 units 450 units
Then 144x = 3060000, or x = $21,250 (answer)