In a stall, some frisbees and mini-helicopters were on sale. ¹₅ of the items were frisbees. ¹₃ of the frisbees and 276 mini-helicopters were sold. There were ¹₆ of the items left in the stall. How many frisbees and mini-helicopters were there in the stall at first?

	Frisbees	Mini-helicopters	Total
Comparing frisbees  and mini-helicopters at first	1x6 = 6 u	4x6 = 24 u	5x6 = 30 u
Before	3x2 =  6 u		6x5 = 30 u
Change	- 1x2 = - 2 u	- 276	- 5x5 = - 25 u
After	2x2 = 4 u	1 u	1x5 = 5 u

 
The total number of toys at first is repeated.  Make the total number of toys at first the same. LCM of 5 and 6 is 30.

The number of frisbees at first is repeated.  Make the number of frisbees the same. LCM of 6 and 3 is 6. 

Number of mini-helicopters left
= 5 u - 4 u
= 1 u

Number of mini-helicopters sold
= 24 u - 1 u
= 23 u

23 u = 276

1 u = 276 ÷ 23 = 12

Number of frisbees and mini-helicopters at first
= 30 u
= 30 x 12
= 360

Answer(s): 360