Verified answer

r = 5 - 2 = 3

a1 = 2

a20 = a1 + 19r

a20 = 2 + 19.3

a20 = 2 + 57 = 59

S20 = (2 + 59).20/2

S20 = 61.10 = 610

a1=2

r=5-2=3

a20=a1+19r

a20=2+19*3

a20=2+57

a20=59

sm=(2+59)/2*20

sn=(61/2)*20

sn=61*10

sn=610