8 x 8 + 13 = 77
88 x 8 + 13 = 717
888 x 8 + 13 = 7117
8888 x 8 + 13 = 71117
88888 x 8 + 13 = 711117
888888 x 8 + 13 = 7111117
8888888 x 8 + 13 = 71111117
......................... and so on
Note:
(88888......)*8 + 13 = 711....1117
If numbers of 8s in bracket of LHS is "n" then number of 1s in RHS is (n-1)
You might get a question in your examination
(888........is a 101 digits number)*8 + 13 = N
then, what would be sum of digits of N?
Ans: 114
Sol: Since there are 101 8s in LHS so there should in 100 1s in RHS sandwiched between two 7s.
So, total digit sum = 7 + 100*1 + 7 = 114
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