Question

A boy says ," I have as many brothers as sisters. " His sister says ," I have twice as as many brothers as sisters ." How many brothers and sisters are there in this family?

Answer 1

let no. of brothers = x, no. of sisters=y

by question,
(x-1) = y [when the boy says, he himself be not counted]

2(y-1) = x [ as the says he has twice the brothers]

therefore, y =x -1 ........eq) &
2y-x =-2 ...........eq2)

putting the value of y in eq2)
2(x-1) - x =2
or x = 2+2 =4

now y= x-1 = 4-1=3

brothers =4 sisters = 3 Ans.