Find the number of ways in which a batsman can score 14 runs in 6 balls

Find the number of ways in which a batsman can score 14 runs in 6 balls not scoring more than 4 runs in any ball
Ans:19C5-614C5+159C5

2 Answers

11
Devil ·

Coefficient of x^{14} in (1+x+x^2+x^3+x^4)^6
is the reqd number of ways.
Don't ask me to find this - coz I'm bound to err!

24
eureka123 ·

@karan...
see on every ball batsman can score 0run,1 run....6runs
and we have six balls
also total runs =14

so no. of ways = coeff of x14 in (x0+x1+...+x6)(x0+x1+...+x6)(x0+x1+...+x6)(x0+x1+...+x6)(x0+x1+...+x6)(x0+x1+...+x6)

=>no. of ways = coeff of x14 in (x0+x1+...+x6)6

But max runs off each ball =4
so we cant have x5 and x6

=>no. of ways=coeff of x14 in (x0+x1+...+x4)6

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