Answer :
Answer:
To help find a percent of a whole number
1. out output value is 400
2. we represent the unkown value with x
3. from step 1 above 400=100%
4. similarly, x=40%
5. This results in a pair of simple equations
400=100%(1)
x=40%(4)
6. By dividing equation 1 by equation 2 and noting that both the RHS (right hand side) of both equations have the same unit (%); we have
[tex]\frac{400}{x} = \frac{100}{40}[/tex]
7. Again, the reciprocal of both sides gives
[tex]\frac{4}{400} = \frac{40}{100}[/tex]
⇒ x=160
Therefore, 40% of 400 is 160
