All of the given questions(#65 to #70) are AP(s).
Formula to be used: a(n) = a(1) + (n - 1)d
Pronounced as:
nth term = 1st term + (n - 1)d, where d is the common difference.
*d = difference of any two consecutive terms.
65):
1st term = 2, d = 6 - 2 = 4
Therefore,
11th term = 2 + (11 - 1)4 = 42
66):
1st term = 5, d = 15 - 5 = 10
Therefore,
16th term = 5 + (16 - 1)10 = 155
67):
1st term = 19, d = 39 - 19 = 20
Therefore,
21st term = 19 + (21 - 1)20 = 419
68):
1st term = 8, d = 38 - 8 = 30
Therefore,
36th term = 8 + (36 - 1)30 = 1058
69):
1st term = 1/2, d = 1 - 1/2 = 1/2
Therefore,
101st term = 1/2 + (101 - 1)1/2 = 101/2
70):
1st term = 0.75, d = 1.50 - 0.75 = 0.75
Therefore,
151st term = 0.75 + (151 - 1)(0.75) = 113.25