Hey rachel,

Following pls find my worked solution ( Work Backwards method ).

Start from where A,B had equal amount of money

<after>

A: |---------------|

B: |---------------|

<process>

Working backwards, B gave (1/5) to A, and left with (4/5). So divide B into 4p; likewise for A. Add back 1p to B, while removing 1p from A. So B --> 5p, A --> 3p.

A: |--|--|--|

B: |--|--|--|--|--|

A gave (3/5) to B, and left with (2/5). Divide the 3p of A into 6u (i.e. 1p --> 2u). So A --> 6u; Likewise, B --> 5p x 2 = 10u. As (2/5) --> 6u, (5/5) --> 15u. So add back 9u to A, while remove 9u from B. So A --> 15u, B --> 1u.

Hence, the <before> model is as follows:

*** - buffer space for alignment purpose

***<------ 15u ------>

A: |--|--|--|--|--|--|--|-|

B: |-|

Given A,B shared a total sum of $200 at first, we have ...

16u --> 200

1u --> 12.50

A (at first) = 15u --> 15 x 12.50 = **$187.50**

===========================

Trust this helps.

Do let me know again if there's any clarification.

Cheers,

Edward