Ben saved $4 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: 4, 11, 18, 25, 32, 39, 46, 53, 60
Using rainbow method: 4 + 60 = 6411 + 53 = 6418 + 46 = 6425 + 39 = 64Sum of each pair = 64Number of pairs: 4, left: 32 Sum of all pairs = [64 x 4] + 32 = 256 + 32 = $288 Answer(s): $288