sum as 6973.which d 7 and 22nd term is 149.difference of the given AP. Then,Hence, there are 38 terms in the AP having their7. Find the sum of first 22 terms of an AP inSol. Let a be the first term and d the commond7 and α22-149a + (22 1)d 149

sum as 6973.which d 7 and 22nd term is 149.difference of the given AP.

1.	sum as 6973.which d 7 and 22nd term is 149.difference of the given AP. Then,Hence, there are 38 terms in the AP having their7. Find the sum of first 22 terms of an AP inSol. Let a be the first term and d the commond7 and α22-149a + (22 1)d 149
Answer» Given d = 7,22nd term =149 ,⇒ a+21d = 149⇒a+21(7) = 149⇒a+147 = 149⇒a=149-147=2Sn = (n/2)(2a+(n-1)d)S₂₂ = (22/2)(2×2+(22-1)7)S₂₂ = 11(4+21(7))S₂₂ = 11(4+147)S₂₂ = 11(151)S₂₂ = 1661.