Question

Carlon plans to evaporate a number of gallons of water from 90 gallons of a 15% salt solution to make a 25% salt solution. Which equation can he use to find x, the number of gallons that should be evaporated?

the options are
1. 13.5/90-x = 25/100
2. 13.5/x =25/100
3. 13.5(90-x) = 0.25
4. 13.5(90-x) = 25

Answer 1

A

first option is correct

Answer 2

Amount of salt = 0.15 x 90
= 13.5

Amount of water evaporated = x
Amount of water after evaporation = 90 - x
Percentage salt = 13.5 / (90 - x)
13.5 / (90 - x) = 25/100

The first option is correct.