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103. A person writes a letter to four of his friends. He asks each one of them to copy the letter and mail to four different persons with instruction that they move the chain similarly. Assuming that the chain is not broken and that it costs 50 paise to mail one letter. Find the amount spent on the postage when 8th set of letter is mailed.

0 5 Views | Posted 6 months ago
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  • 1 Answer

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    Answered by

    Payal Gupta | Contributor-Level 10

    6 months ago

    103. As the number of letters mailed forms a G.P. i.e., 4, 42, ……., 48

    We have,

    a = 4

    r=424=4

    and n = 8

    So, Total numbers of letters = 4 + 43 + ……. + 48

    =4 (48−1)4−1

    =4× (65536−1)3

    =43×65535

    =48×21, 845

    = 87380

    As amount spent on one postage = 50 paise = ?  50100

    So, for reqd. postage =?  50100×87380

    =? 43690

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