Question 1209894
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I'll do the first question to get you started.


x = some unknown number
(2/5)x = two fifths of that number, "of" means "multiply"
4 = (2/5)x
5*4 = 2x
20 = 2x
x = 20/2
x = <font color=red>10</font>
4 is 2/5 of <font color=red>10</font>


As a check,
(2/5)x = (2/5)*10 = (2*10)/5 = 20/5 = 4
The answer is confirmed.
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