please help me sure I will mark you braveliest . Consider the arithmetic sequence 95, 90, 85, 80 ...
a) what is its common difference?(I know the answer)
b) find the sum of terms from 20 th to 40?
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Common difference = d = 90-95 = 85-90 = -5.
Sum of 20-40 = sum of 40 - sum of first 20.
=> 40/2 [ 190 + (39)-5] = 20*-5 = -100.
20/2 [ 190 + 19*-5] = 10*95 = 950.
Hope this answer helps you. Please mark as brainliest! :)
Sum of 20-40 = sum of 40 - sum of first 20.
=> 40/2 [ 190 + (39)-5] = 20*-5 = -100.
20/2 [ 190 + 19*-5] = 10*95 = 950.
Hope this answer helps you. Please mark as brainliest! :)
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