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\(20 + \frac{1}{4} * 20 + \frac{1}{4} * 20 + (\frac{1}{4})^2 * 20 + ....\)

\(20 + 5 + 5 + \frac{5}{4} + \frac{5}{4} + \frac{5}{16} + \frac{5}{16}+ .....\)

\(20 + 10 + \frac{10}{4} + \frac{10}{16} + .....\)

\(20 + [10 + \frac{10}{4} + \frac{10}{16} + ......\)This forms G.P. with a common ratio of \(\frac{1}{4} = 0.25\) and first term as 10]

Sum of G.P. (infinity) = \(\frac{10 }{ 1 - 0.25} = \frac{40 }{ 3}\)

\(20 + \frac{40}{3} = \frac{100}{3} = 33.33\)

Answer C
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20+1/4∗20+1/4∗20+(1/4)2∗20+....20+1/4∗20+1/4∗20+(1/4)2∗20+....

20+10+10/4+10/16+.....20+10+10/4+10/16+.....

20+[10+10/4+10/16+......20+[10+10/4+10/16+......This forms G.P. with a common ratio of 1/4=0.25
as the common ratio and first term as 10]

a/1-r (sum of infinite series ) = 10/1−0.25=403101−0.25=40/3

20+40/3=100/3=33.33
Hence IMO C
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