Question

a chemist has a solution that is 20 percent alcohol by volume. which of the following expressions represents the percent of alcohol by volume when m litersof the solution is mixed with h liters of pure alcohol and p liters of water?

a) 20(m+h+p)%
b) 20(m+h)/m+h+p)
c)20?h+p
d) 20m/h+p
e) 20m+100h/m+h+p

please explain

Answer 1

let's look at how much alcohol we have

we have .2m + h + 0.0p = .2m+h

what is the total volume ?
= m+h+p

so the percentage is (.2m+h)/(m+h+p)(100%)
= (20m + 100h)/(m+h+p)%

I suppose e) resembles that if it had the brackets