Mark and Eric were given some allowances each. If Mark spent $12 each day and Eric spent $36 each day, Mark would still have $2485 left when Eric spent all his allowance. If Mark spent $36 each day and Eric spent $12 each day, Mark would still have $85 left when Eric spent all his allowance.

1. How much allowance did Mark receive?
2. How much allowance did Eric receive?

	Case 1		Case 2
	Mark	Eric	Mark	Eric
Before	1 u + 2485	3 u	3 p + 85	1 p
Change	- 1 u	- 3 u	- 3 p	- 1 p
After	2485	0	85	0

(a)
Simplify the ratio.
12 : 36 = 1 : 3

The allowance that Eric had at first is the same for Case 1 and Case 2.

1 p = 3 u
3 p = 9 u

The allowance that Mark had at first is the same for Case 1 and Case 2.

9 u + 85 = 1 u + 2485
9 u - 1 u = 2485 - 85
8 u = 2400

1 u = 2400 ÷ 8 = 300

Allowance that Mark received
= 1 u + 2485
= 300 + 2485
= $2785

(b)
Allowance that Eric received
= 3 u
= 3 x 300
= $900

Answers: (a) $2785; (b) $900