How to solve logic problems

1
How to solve logic problems
Three children live in the same street. From the
clues given below, can you discover each
childs full name and age? Clues 1. Miss Brown
is three years older than Mary. 2. The child
whose surname is White is 9 years old.
2
Solution
Miss Brown (clue 1)cannot be Brain, so you
place an ? in the Brain/Brown box.
Brown
Green
White
7
9
10
Anne
?
?
?
Brain
?
Clue 1 tells us that she is notMary either, so
you can put an ? in the Mary/Brown box.
?
Mary
7
Miss Brown is therefore Anne, the only possible
remaining. Now you place a ? in that box in
the chart, with corresponding ?s against the
other possible surnames for Anne
9
10
3
Solution (contd)
If Anne Brown is three years older then Mary
(clue 1), she must be 10 and Mary 7. So place ?
in the Anne/10, Brown/10 and Mary/7 boxes, and
?s in all the empty boxesin each row and column
containingthese ?s .
Brown
Green
White
7
9
10
Anne
?
?
?
?
?
?
Brain
?
?
?
?
?
?
?
?
?
?
?
?
Mary
The chart now reveals Brainsage as 9, so you
can place a ? in theBrain/9 box and an ? in the
two other box .
7
?
?
?
Clue 2 tells us that White is 9 years old, so he
must be Brain. Place ? in White/9 and
Brain/White.
9
?
?
?
10
?
?
?
You can see now that the remaining unfilled boxes
in the chart must contain ?s, so they reveal
Green as the surname of 7-years old Mary.