Question

for an A.P., if a=5 and d=7, then T20
(a)107
(b)145
(c)102
(d)138

Answer 1

tn=a+(n-1)d
t20=5+(20-1)7
t20=5+19×7
t20=5+133
t20=138

and hence option (d) is the correct answer