Mrs. McCarthy does not feel herself very comfortable
in algebra. So that, the most resonable way for her to figure
out the March 1st balance is by working backwards.
    She knows that  her April 1st balance  was  $672. For the
correct  solution of  the problem, it does not matter  if she
deposited  $150 in one day,  in two days, or  in  three sepa-
rate days.
    Therefore, the amount  of  money in  her  account  before
these deposits was: $672 - $150 = $522 .  So , she  left $522
in her account  after taking 1/3 of the sum.  $522  is 2/3 of
the sum of money she had in her account at March 1st :
    Mrs.McCarthy's  balance  of  March  1st  was 3/2 of $522.
Since 1/2 of $522 is $261, therefore 3/2 of 522 is
$522 + $261 = $783.
    Thus, Mrs.McCarthy's balance of March 1st was $783.

    Mary = Tom +2
    Tom = 3 Susan
    Susan = Joe/4
    Mary =3 * 4/4 +2; Mary = 5

Team 4     10
Team 3     10 x 2 = 20  (Number of cars to be wash; thus
                         Team 2 washed 40 cars)
Team 2     20 x 3 = 60  (2/3 of 60 is 40; Team  3 washed
                         1/2 the cars left by Team 2)
Team 1     60 x 2 = 120 (1/2 of the total; so we multip-
                         ly by 2)

The four teams washed 120 cars.