Find the 60th term of the AP 8,10,12,…, if it has a total of 60 terms and hence find the sum of its last 10 terms.
Answers
Answered by
0
Answer:
240.............................................
Answered by
6
Answer:
126, 1170
Step-by-step explanation:
aₓ = a+(x-1)d
x=60, a=8, d=2
a₆₀ = 8+(60-1) 2
a₆₀ = 8+59×2
a₆₀ = 8+118
a₆₀ = 126
Sum of first x terms of an AP =
Sₓ = x/2 [2a+(x−1)d]
Using formula
S₆₀ = 60/2[2×8+(60−1)×2]
= 4020
Similarly
S₅₀ = 50/2[2×8+(50−1)×2]
= 2850
Sum of last 10 terms
= S₆₀ − S₅₀
= 4020 – 2850
= 1170
hope it helps....
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