Question 1060582
What's a can of sofa?
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4:5 means that out of every 9, 4 are one and 5 the other. So, how many groups of 9 are there in 45? 45/9 = 5 
So we have 5 groups of 9, and each group has 4 of one and 5 of the other
5 groups times 4 of one = 5*4 = 20 cans in this group
5 groups times 5 of the other = 5*5 = 25 cans in this other group