T H R _ _
S _ S T _ R S
_ N D
T W _
B R _ T H _ R S .
T H _ S
C _ N
B _
S _ L V _ D
B Y
S _ M P L _
D _ D _ C T _ _ N ,
B _ T
_ F
_ L G _ B R _
_ S
_ S _ D
L _ T
X
B _
T H _
N _ M B _ R
_ F
S _ S T _ R S
_ N D
Y
T H _
N _ M B _ R
_ F
B R _ T H _ R S :
X +
1 =
2 Y
Y +
1 =
X
T H _ R _ F _ R _ ,
Y
+
1 +
1 =
2 Y
S _
Y
= 2
_ R
X
+
1 =
2 X
-
2
S _
X
=
3 Clue
FOUR BROTHERS AND THREE SISTERS. EVERY BOY WILL HAVE 3 BROTHERS AND 3 SISTERS. EVERY GIRL WILL HAVE 4 BROTHERS AND 2 (HALF OF THE NUMBER OF BROTHERS) SISTERS THREE SISTERS AND TWO BROTHERS. THIS CAN BE SOLVED BY SIMPLE DEDUCTION, BUT IF ALGEBRA IS USED LET X BE THE NUMBER OF SISTERS AND Y THE NUMBER OF BROTHERS: X+ 1= 2Y Y+ 1= X THEREFORE, Y + 1+ 1= 2Y SO Y =2 OR X + 1= 2X - 2 SO X = 3 THERE ARE 4 SISTERS AND 3 BROTHERS. JULIE HAS 3 SISTERS AND 3 BROTHERS, AND PETE HAS 2 BROTHERS AND 4 SISTERS FOUR DAUGHTERS AND THREE SONS. EACH DAUGHTER HAS 3 SISTERS AND 3 BROTHERS, AND EACH BROTHER HAS 2 BROTHERS AND 4 SISTERS