Question 1012095

The fourth term of a geometric series is 10 and the seventh term is 80.
Find the common ratio, the first term and the sum of the first 20 terms( tl the nearest whole number) 

James
<pre>1<sup>st</sup> term, or {{{highlight_green(a[1] = 1.25)}}}
r, or common ratio = {{{highlight_green(2)}}}
Sum of 1<sup>st</sup> 20 terms = 1,310,718.75 &#8776; {{{highlight_green(1310719)}}}