Neave saved $4 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: 4, 7, 10, 13, 16, 19, 22, 25, 28
Using rainbow method: 4 + 28 = 327 + 25 = 3210 + 22 = 3213 + 19 = 32Sum of each pair = 32Number of pairs: 4, left: 16 Sum of all pairs = [32 x 4] + 16 = 128 + 16 = $144 Answer(s): $144