Which term of the AP 9, 14, 19,24, 29, …. is 379?
To Find: we need to find n when an = 379
Given: The series is 9, 14, 19,24, 29, …. and an=379
a1=9, a2= 14 and d=14–9 = 5
(Where a=a1 is first term, a2 is second term, an is nth term and d is common difference of given AP)
Formula Used: an = a + (n - 1)d
an= 379 = a1 + (n–1)5
379 – 9 = (n–1)5 [subtract 9 on both side]
370 = (n–1 � � �)5
74 = (n–1) [Divide both side by 5]
n = 75th
The 75th term of this AP is equal to 379.