14
First term = 6(1) - 4 = 2
16th term = 6(16) - 4 = 92
Sum =
(first term + last term) (number of terms) / 2 =
(2 + 92) * 16/2 = 94 * 8 = 752
15. Similar to 14
First term = 4(1) - 3 = 1
!0th term = 4(10) - 3 = 37
Sum =
(1 + 37) * 10/ 2 =
38 * 5 =
190
