Karen has 4h storyboiks. karen's storybook collection is 2/3 of what mary's collection is. how many storybooks do they have in all?

In order to find out the answer , you just need to count :
Let's say that mary's collection is symbolized by x

2/3  x     =   4h

x             = 3/2 . 4h

x           =    6h

The storybooks they have in total would be : 6h  + 4h = 10 h

hope this helps

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