In a supermarket, the prices of pastries are listed as follow:

Pastry Prices
Scone	$1
Tart	$3
Puff	$4

The ratio of the number of scones sold to the number of tarts sold was 5 : 4. The ratio of the number of puffs sold to the number of tarts sold was 7 : 3. The supermarket collected $39 more on the sales of puffs than the sales of scones.

1. How many scones were sold?
2. How much did the supermarket collect from the sales of the pastries?

Scones	Tarts	Puffs
5x7	4x7
	7x4	3x4
35 u	28 u	12 u

	Scones	Tarts	Puffs
Number	35 u	28 u	12 u
Value	1	3	4
Total value	35 u	84 u	48 u

(a)
The number of tarts sold is repeated.  Make the number of tarts the same.  LCM of 4 and 7 is 28.

Amount that the supermarket collected more from the sales of the puffs than the scones
= 48 u - 35 u
= 13 u

13 u = 39

1 u = 39 ÷ 13 = 3

Number of scones that the cafe sold
= 35 u
= 35 x 3
= 105

(b)
Amount that the supermarket collected from the sales of the pastries
= 35 u + 84 u + 48 u
= 167 u
= 167 x 3
= $501

Answer(s): (a) 105; (b) $501