22
(This was a 1 mark question in the CBSE Class X board examination in 2017.)
What is the common difference of an A.P. in which a21 - a7 = 84?
Answers
Answered by
3
Answer:
Step-by-step explanation:
a21=a+(21-1)*d=a+20d
a7=a+(7-1)*d=a+6d
given
a21-a7=84
a+20d-a-6d=84
14d=84
d=6
Answered by
0
Answer:
6
Step-by-step explanation:
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