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What is the difference between the sum of 1st 20 terms and the next 20 terms of the arithmetic sequence 6, 10 , 14, ... |
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Answer» Step-by-step explanation: 6 , 10 , 14 , …… is the AP 1st term 6 , common diff=10–6=4 21 ST term = 6+(21–1)×4=86 20 TH term=86–4=82 40 th term = 6+(40–1)×4=6+39×4= =156+6=162 sum of 21 st to 40 th term ie 20 terms =(86+162)20/2=248×10=2480 sum of first 20 terms =(6+82)×20/2=880 difference =2480–880=1600 |
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