Answer:
40% = 4/10 = 2/5
We can easily see that 60% +40% =100
But in calculi we could always show
x=10
6x + 4x =10x
10x - 4x = 6x
10x -6x =4x
When we add them together
we find 20
20/4 = square of 4 + 4/5
20 + 4 /2 x 3 = square of 6
x(x - 4) = x^2 - 4x
and we see the customers use credit above, where concerned the customers don't use credit we can show
x(x - 6)
x^2 -6x
10^2 - 6x
100 - 60
=40
=4/10
=2/5
Explanation: