This is an arithmetic sequence ( the difference is constant - d ). a 1 = 0.25, a 2 = 0.5, a 3 = 0.75, a 4 = 1,... a n = a 1 + ( n - 1 ) d So: a 1 = 0.25 and d = 0.25 a 3 = 0.25 + ( 3 - 1 ) * 0.25 = 0.25 + 2 * 0.25 = 0.25 + 0.50 = 0.75 Answer: a 3 = 0.75
