The first and the last term of an AP are 5 and 45 respectively. If the sum all the terms is 400 find it's common different
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2
5,10,15.........45
difference=a2-a1
d=10-5
d=5
I hope it will help u.please mark me as a brainliest
difference=a2-a1
d=10-5
d=5
I hope it will help u.please mark me as a brainliest
Answered by
3
A = 5
An = 45
Formula for sum of n terms in AP
Sn = ( n/2 ) * ( First term + Last term )
Since, the sum all the terms is 400
400 = ( n/2 ) * ( 5 + 45 )
400 = ( n/2 ) * ( 50 )
400 = n*25
n = 16
Formula for value of nth term in AP
An = A + (n-1)*D
Now for last term (An = 45),
45 = 5 + (16-1)*D
40 = 15*D
D = 8/3
An = 45
Formula for sum of n terms in AP
Sn = ( n/2 ) * ( First term + Last term )
Since, the sum all the terms is 400
400 = ( n/2 ) * ( 5 + 45 )
400 = ( n/2 ) * ( 50 )
400 = n*25
n = 16
Formula for value of nth term in AP
An = A + (n-1)*D
Now for last term (An = 45),
45 = 5 + (16-1)*D
40 = 15*D
D = 8/3
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