India and South Africa play one day international series until one team wins 4 matches. No match ends in a draw. Let k be the number of ways the series can be won.Find sum of digits of k ?
Open in App
Solution
Taking I for India and S for South Africa. We can arrange I and SA to shown the wins for India and South Africa respectively. e.g. : ISSSS means first match is won by India which is followed by 4 wins by South Africa. This is one way in which series can be won. Suppose South Africa wins the series, then last match is always won by South Africa. ∴ Total number of ways =35 In the same number of ways India can win the series. ∴ Total no. of ways in which the series can be won 35×2=70.