there are 6 positive and 8 negative numbers . 4 numbers are choosen at random and multiplied . the probability that the product is positive is :
6 c 4 / 14 c 4 + ( 6 c 2 * 8 c 2 ) / 14 c 4 + 8 c 4 / 14 c 4 = 505 / 1001 case 1 : only 4 positive no . case 2 : 2 positive and 2 negative no . case 3 : 4 negative no . answer : e
divide(add(add(divide(factorial(6), multiply(factorial(4), factorial(const_2))), divide(factorial(8), multiply(factorial(4), factorial(4)))), multiply(divide(factorial(6), multiply(factorial(4), factorial(const_2))), divide(factorial(8), multiply(factorial(6), factorial(const_2))))), divide(factorial(add(6, 8)), multiply(factorial(subtract(add(6, 8), 4)), factorial(4))))