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Nona    0

I've got the home instructors guide, and it shows two different ways to solve the problem. I don't understand why 6 units equals 48. Where did the six units come from? 

Why did the book multiply the fraction of the left over part of the red and yellow beads to get 10 units instead of subtracting the red and yellow beads from the whole?  

And if we change the units to 20 then the red beads are 5/20 and the yellow beads are 12/20. I subtract those from 20/20 to get 3/20. So 3/20 equals the blue beads. 1/20 equals 16, and the total beads are 320. But, that's not what the book says. 

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Jenny    3

The problem states that 3/5 OF THE REMAINDER are yellow. The remainder after 1/3 is 3/4.  if 3/5 of the remainder is yellow, then 2/5 of the remainder is blue. So you have to find 2/5 of 3/4. 

The reason to divide into 20 units is to get equal units. There are 5 units in the remainder, for blue and yellow, but red is 3 units (of a different size) the 3 units of red, and the 5 of blue and yellow are equal. So if there are 15 units, for both of them, then both red units, and the ones for blue and yellow, are same size. 

Since there were originally 4 units for the red, divide each one up to have 20. 1/4 of 20 is 5 of the units. 15 units remain. Yellow is 3/5 of those remaining units. Which is 9 of them. Leaving 6. So 6 units are the blue beads.

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