Question

A man had Apple.He sold 40 percent he left 420 apples how does apples
he have

Answer 1

Suppose there were 10 apples 
40% sold = 40%of 10= 4 apples
remaining apples = 10-4=6 apples

Now using the unitary method

If 6 apples are left , total apples were = 10
If 1 apple is remaining, total apples would be= 10/6
If 420 apples are remaining. total apples were = $\frac{10}{6}$ X 420= 700

So, Total apples were 700