2) which term of the sequence 20,19,1/4,18 1/2,17 3/4......is the first is negative term
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19 1/4 =77/4 Now,20-77/4 =3/4
18 1/2 =37/2 Now,77/4-37/2 =3/4
17 3/4 =71/4 Now,37/2-71/4 =3/4
So,we have a series where terms get decreased by 3/4 .Means it is A.P.series with a=20 and d=(-3/4).Let nth term be its first negative term.
=> 20 +(n-1)(-3/4) <0
{ in A.P.,nth term =a+(n-1)d
=> 80-3n+3 <0 => 83<3n =>83/3 <n
So, n =28
{first integer greater than 83/3 ~27.6 }.
And 28th term =20+(28-1)(-3/4)
=20+27×(-3/4) = -1/4 Ans.
18 1/2 =37/2 Now,77/4-37/2 =3/4
17 3/4 =71/4 Now,37/2-71/4 =3/4
So,we have a series where terms get decreased by 3/4 .Means it is A.P.series with a=20 and d=(-3/4).Let nth term be its first negative term.
=> 20 +(n-1)(-3/4) <0
{ in A.P.,nth term =a+(n-1)d
=> 80-3n+3 <0 => 83<3n =>83/3 <n
So, n =28
{first integer greater than 83/3 ~27.6 }.
And 28th term =20+(28-1)(-3/4)
=20+27×(-3/4) = -1/4 Ans.
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