Question 22

I       [u][u][u]

G      [u][u][u][u]

S      [u][u][u][u][u]

Total of G + S = 9u = 108   => u = 12

I = 3u = 3 x 12 = 36

Hence Isabelle has 36 badges.

Question 23

B    [u][u][u][u]:u:   where :u: is the amount left which is equal for all 3.

D    [u][u]:u:

C    [225]:u:

(a)   1170 – 6u – 225 = 3u

          9u = 945

             u = 105

       Hence each boy has $105 left in the end.

(b)  3u = 3×105 = 315

        Hence Daniel has $315 at first.