what is the difference between the sum of the first 20 terms and the next 20 terms of the arithmetic sequence 6,10,14...
Answers
Answer:
Step-by-step explanation:
Sequenceis6,10,14…
It is an A.P
Herea1=6,d=4
Tofindout20thterm ,(n=20)
a20=a1+(20−1)d
a20=6+(20−1)4
a20=6+(20−1)4
a20=6+(20−1)4
a20=6+76
a20=82
Sum of first 20 terms
s20=n(a1+a20)/2
s20=20(6+82)/2
s20=(20×88)/2
s20=880
21thtermisa21=a20+d=82+4=86
To find out sum of last 40 term ,we have to find 40th term,
a40=6+(40–1)4
a40=6+39×4
a40=6+156
a40=162
Sum of next 20 terms (from 21st to 40th)
sum=n(a21+a40)/2
sum=20(86+162)/2
sum=(20×248)/2
sum=2480
Therefore difference between sum of last 20 and first 20 terms in the given series
=2480
=1600
Answer is 160
PLEASE MARK AS BRAINLIEST
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