Others Maths Puzzle Numerical Ability

The sum of the first 6 terms of an A.P is zero and the 4th term is 2 then find the sum of its first 30 terms.

Read Solution (Total 1)

1440

If first term=a and difference=d, then
Sum of 6 terms of A.P.=3(2a+5d)=0, 6a+15d=0 ---(i) and
4th term=a+3d=2 ---(ii)
On solving (i) & (ii), d=4, a=-10
So sum of first 30 terms=15[2*(-10) +(29*4)]=1440
9 years agoHelpfull: Yes(3) No(1)

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