1.

Find 8th term of the A.P. 117,104,91,78,....

Answer»

Given A.P is

117,104,91,78,.....

first term of this A.P is  a1​ = 117

second term of this A.P is  a2 ​= 104

 common difference of an A.P is given by

(i.e., d = an+1​−an​)

putting n = 1 in above equation

d = a2​−a1 ​= 104−117 = −13

hence common difference for this A.P is d = −13

the nth term of an A.P is given by.

an​=a1​+(n−1)d

⟹an​=117+(n−1)(−13)

⟹an​=117−13n+13

⟹an​=130−13n....eq(1)

for finding 10th term (a8​)of this A.P put n=8 in above eq(1)

⟹a8​=130−13×8

⟹a8​=130−104

⟹a8​=26



Discussion

No Comment Found

Related InterviewSolutions