find the 31st term of an AP whose 11th term is 38 and the 16th term
Answers
Answered by
4
Answer:
178
Step-by-step explanation:
Given that, a11=38 a16=73
We know that,
an=a+(n−1)d
a11=a+(11−1)d
38=a+10d ... (i)
Similarly,
a16=a+(16−1)d
73=a+15d ... (ii)
On subtracting (i) from (ii), we get
35=5d
∴d=7
From equation (i),
38=a+(10)(7)
⇒38−70=a
∴a=−32
Now a31=a+(31−1)d
=−32+30(7)
=−32+210
=178
Hence, 31st term is 178
Similar questions