Answer
Given
$a_{n}$ = $a_{n - 1}$ - 10.
$a_{1}$, the first term = 30
$20^{th}$ term of sequence = -160
Work Step by Step
Given
$a_{n}$ = $a_{n - 1}$ - 10.
$a_{1}$, the first term = 30
$2^{nd}$ term of sequence = $a_{1}$ - 10 = 30 - 10 = 20
$3^{rd}$ term of sequence = $a_{2}$ - 10 = 20 - 10 = 10
$4^{th}$ term of sequence = $a_{3}$ - 10 = 10 - 10 = 0
$5^{th}$ term of sequence = $a_{4}$ - 10 = 0 - 10 = -10
$6^{th}$ term of sequence = $a_{5}$ - 10 = -10 - 10 = -20
$7^{th}$ term of sequence = $a_{6}$ - 10 = -20 - 10 = -30
$8^{th}$ term of sequence = $a_{7}$ - 10 = -30 - 10 = -40
$9^{th}$ term of sequence = $a_{8}$ - 10 = -40 - 10 = -50
$10^{th}$ term of sequence = $a_{9}$ - 10 = -50 - 10 = -60
$11^{th}$ term of sequence = $a_{10}$ - 10 = -60 - 10 = -70
$12^{th}$ term of sequence = $a_{11}$ - 10 = -70 - 10 = -80
$13^{th}$ term of sequence = $a_{12}$ - 10 = -80 - 10 = -90
$14^{th}$ term of sequence = $a_{13}$ - 10 = -90 - 10 = -100
$15^{th}$ term of sequence = $a_{14}$ - 10 = -100 - 10 = -110
$16^{th}$ term of sequence = $a_{15}$ - 10 = -110 - 10 = -120
$17^{th}$ term of sequence = $a_{16}$ - 10 = -120 - 10 = -130
$18^{th}$ term of sequence = $a_{17}$ - 10 = -130 - 10 = -140
$19^{th}$ term of sequence = $a_{18}$ - 10 = -140 - 10 = -150
$20^{th}$ term of sequence = $a_{19}$ - 10 = -150 - 10 = -160