1.

Let S=`4/19+44/(19)^2+444/(19)^3+...oo` then find the value of SA. `40//9`B. `38//81`C. `36//171`D. none of these

Answer» Correct Answer - B
`S=4/19+44/19^(2)+444/19^(3)+…` (1)
`rArr1/19S=4/19^(2)+44/19^(3)+…` (2)
Subtracting (2) from (1), we get
`18/19S=4/19+40/19^(2)+400/19^(3)+…`
`=(4/19)/(1-10/19)=4/9`
`rArrS=38/81`


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