class 10 maths chapter 5 exercise 5.2 question 7 in hindi
हल:-
माना कि उस A.P का प्रथम पद a और सार्वअंतर d है ।
प्रश्न के अनुसार,
Ap का 11 पद 38 है
मतलब, a11=38
a+10d=38 ............(i)
and 16th term is 73.
means, a16=73
a+15d=73 .............(ii)
From Equ (i) & (ii)
a+10d=38 ............(i)
a+15d=73 .............(ii)
After solving,
-5d=-35
5d=35
d=7
value of d put in equation (i)
a+10×7 =38
a= 38-70
a=-32
now the 31st term of an AP
means, a31=a + 30d
a31=-32 + 30×7
a31=-32 +210
a31= 178
Hence the 31st term of an AP=178
