Tom, Albert and Daniel have some erasers. The ratios of their erasers are as follows:

Tom : (Tom + Albert + Daniel) = 3 : 7
Albert : (Tom + Daniel) = 1 : 3

Daniel has 24 erasers more than Albert. In the end, Daniel gives away all he has to Albert and Tom so that both Albert and Tom end up with the same number of erasers, how many erasers has Albert received from Daniel?

Albert	Daniel	Tom	Total
4x4		3x4	7x4
1x7	3x7		4x7
7 u	9 u	12 u	28 u

The total number of erasers is repeated.  Make the total number of erasers the same.  LCM of 7 and 4 is 28.

Number of erasers that Daniel has more than Albert
= 9 u - 7 u
= 2 u

2 u = 24

1 u = 24 ÷ 2 = 12

	Albert	Daniel	Tom
Before	7 u	9 u	12 u
Change	+ 7 u	- 9 u	+ 2 u
After	14 u	0 u	14 u

Number of erasers that Albert has received from Daniel
= 14 u - 7 u 
= 7 u
= 7 x 12
= 84

Answer(s): 84