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Find the sum of first 15 terms of AP 2, 5, 8, 11, .......
Answers
Answered by
11
Answer:
345
Step-by-step explanation:
a= 2 d = 3
sum =( n÷2)×(2a+(n- 1)d)
=( 15÷2)×(2×2 +(15-1)×3)
= 15×23
= 345
Answered by
6
Answer:
330
Step-by-step explanation:
it is in AP
a=2
d=t2-t1
d=5-2
d=3
sn=n/2(2a+(n-1) d)
s15= 15/2(2×2+(15-1)3)
s15=15/2(4+14×3)
s15=15/2(4+42)
s15=15/2(44)
s15=15×22
s15=330
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