Find the sum of series 72+70+68+.....+40.
Answers
Answered by
36
SOLUTION
Given,
a=72
d= -2
l= 40
Therefore,
l= a+(n-1)d
=) 40= 72(n-1)(-2)
=) 40= 72-2n+2
=) 2n= 34
=) n= 34/2
=) n= 17
Now,
the required sum of n terms Sn
hope it helps ☺️
Answered by
0
Answer:
952 is your answer
Step-by-step explanation:
first term, a1 = 72
common difference, d = 70 - 72 = -2
Number of terms, n = (an - a1)/d + 1 = (40-72)/-2 + 1 = 32/2 + 1 = 17
Sum = n/2 * (a1 + an) = 17/2*(72+40) = 952
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