In a store, some rubber duckies and flying saucers were on sale. ¹₁₀ of the items were rubber duckies. ²₃ of the rubber duckies and 740 flying saucers were sold. There were ¹₉ of the items left in the store. How many rubber duckies and flying saucers were there in the store at first?

	Rubber duckies	Flying saucers	Total
Comparing rubber duckies  and flying saucers at first	1x9 = 9 u	9x9 = 81 u	10x9 = 90 u
Before	3x3 =  9 u		9x10 = 90 u
Change	- 2x3 = - 6 u	- 740	- 8x10 = - 80 u
After	1x3 = 3 u	7 u	1x10 = 10 u

 
The total number of toys at first is repeated.  Make the total number of toys at first the same. LCM of 10 and 9 is 90.

The number of rubber duckies at first is repeated.  Make the number of rubber duckies the same. LCM of 9 and 3 is 9. 

Number of flying saucers left
= 10 u - 3 u
= 7 u

Number of flying saucers sold
= 81 u - 7 u
= 74 u

74 u = 740

1 u = 740 ÷ 74 = 10

Number of rubber duckies and flying saucers at first
= 90 u
= 90 x 10
= 900

Answer(s): 900