Any guidance or worked solutions would be appreciated 1. The problem statement, all variables and given/known data For a potato race, a straight line is marked on the ground from a point A, and points B,C,D,... are marked on the line so that AB = BC = CD = ... = 2 metres. A potato is placed at each of the points B,C,D,... A runner has to start from A and bring each potato by a separate journey back to a basket at A. Find the number of potatoes so that the total distance run during the race will be 480 metres. 2. Relevant equations A) S = n/2 [2a + (n - 1) d] B) S = n/2 [ first term + last term] 3. The attempt at a solution I can calculate the answer by listing out the distances covered in successive trips to obtain the required distance. However, I am unable to show relevant working and this method will not work for larger sequences. *Tn* = 2n(n+1), where *Tn* is the 'n' th term in the sequence. The problem is I can't find a relevant equation for the common difference, let's say, *d*. *d* = 4(n+1) ? I can't use equation B) as the common difference is not a constant.