Question 965723
In a potato race, 10 potatoes are placed in a straight line 5 meters apart, the
first potato being placed 6 meters from the starting point. How many meters does
a contestant travel in collecting the potatoes one at a time and placing them in
a basket located at the starting point ?
<pre>
For the first potato he travels 6 meters up and 6 meters back, 
so the first term of the sequence is 12.

For the second potato in addition to the 12 m, he travels 5 m 
more up and 5 m more back, so that's 12+10 or 22 m.  So the 
common difference is 10 m.

We have an arithmetic sequence with {{{a[1]=12}}}, {{{d=10}}}, {{{n=10}}}

{{{S[n]=expr(n/2)(2^""a[1]+(n-1)d)}}}
{{{S[10]=expr(10/2)(2^""*(12)+(10-1)(10))}}}
{{{S[10]=5(24^""+(9)(10))}}}
{{{S[10]=5(24+90)}}}
{{{S[10]=5(114)}}}
{{{S[10]=570}}}

Answer 570 meters

Edwin</pre>