A+ Maths Question

[11is1louder]

find and algebraic formular to find C...
the formular to find D was D=12*(0.8)n-1 but has nothing to do with C....

i think thats about it... A+ question good luck

N D C
1 12 12
2 1.6 13.6
3 0.8 14.4
4 0.4 14.8
5 0.2 15
6 0.1 15.1
7 0.05 15.15

[OfficeShredder]

Let's look at C_n - C_(n-1)

1.6
.8
.4
.2
.1
.05

starting to see a pattern?