Use the simplest rule you can find to calculate the next three terms of the following sequence. 15, 24, 35, 48, a. 126, 252, 504b. 80, 99, 120c. 48, 35, 15d. 82, 90, 98

15, 24, 35, 48, 63,

a1 = 15

a2 = a1 + 2 * 4 + 1 =  15 + 9 = 24

a3 = a2 +  2 * 5 + 1 =  24 + 11 = 35

a4 = a3 +  2 * 6 + 1 =  35 + 13 = 48

a5 = a4 +  2 * 7 + 1 =  48 + 15 = 63

and so on

so

an = a(n - 1) + 2(n +1) + 1

a6 = a5 + 2(6 + 2) + 1 = 63 + 16 + 1 = 80

a7 = a6 + 2(7 + 2) + 1 = 80 + 18 + 1 = 99

a8 = a7 + 2(8 + 2) + 1 = 99+ 20 + 1 = 120

Next 3 terms should be  80, 99, 120

Answer

B. 80, 99, 120