Dylan saved $3 in the first week and increased his savings by $3 each week. How much would he have saved at the end of 9 weeks?
Make a list: 3, 6, 9, 12, 15, 18, 21, 24, 27
Using rainbow method: 3 + 27 = 306 + 24 = 309 + 21 = 3012 + 18 = 30Sum of each pair = 30Number of pairs: 4, left: 15 Sum of all pairs = [30 x 4] + 15 = 120 + 15 = $135 Answer(s): $135