Jack saved $6 in the first week and increased his savings by $7 each week. How much would he have saved at the end of 9 weeks?
Make a list: 6, 13, 20, 27, 34, 41, 48, 55, 62
Using rainbow method: 6 + 62 = 6813 + 55 = 6820 + 48 = 6827 + 41 = 68Sum of each pair = 68Number of pairs: 4, left: 34 Sum of all pairs = [68 x 4] + 34 = 272 + 34 = $306 Answer(s): $306
