If sea water contains 3.5% of salt. how much seawater do you need in order to get 17.5 lb of salt?

500 lb

Step-by-step explanation:

Let x lb be the weight of seawater needed to get 17.5 lb of salt.

Now,

x lb - 100%

17.5 lb - 3.5%

Write a proportion:

Cross multiply:

set each factor equal to 0

4x-3 = 0

2x-1 = 0

solve for x.

4x-3=0

4x=3

x= 3/4

solve for x. 

2x-1= 0

2x= 1

x= 1/2

your answer should be 1/2 is less than or equal to x and 3/4 is greater than or equal to x