Question

Ben, Bob and Bill are triplets. They were born 5 years before their sister, Stephanie. This year the product of their four ages is 75749 greater than the sum of their ages. How old is Stephanie? Show all your work.

Answer 1

Let the triplets' age be x, the sister's age is then x-5. 
product of their age as given 
xÂł.(x-5)=75749+x+x+x+x-5
 x^4 - 5xÂł= 4x +75744
 x^4 - 5xÂł -4x -75744=0
 resolving the equation,
 we get 
 x = 18 
 therefore, Age of ben,bob and bill is 18
 so , age of stephanie is x-5 = 18-5 = 13
 stephanie is 13 years old.