The below questions were taken from two paper tests, i know the answer however wanted to see if anyone could solve based on the attached "Mixture Problems Made Easy"

The attached works great for mixture problems

How many gallons of water must be mixed with 1 gallon of a 15% salt solution To obtain a 10% salt solution

A. 5

B. 67

C. 1.00

D. 1.50

E. 2.00

One fourth of a solution that was 10% sugar by weight was replaced with by a second solution resulting in a solution that was 16 percent sugar by weight. The second solution was what percent sugar by weight?

A. 34%

B. 24%

C. 22%

D. 18%

E. 8.5%

for this problem based on the attached method, which this problem and the one below appear,

i understand how to get (x-16):6

but how do i get to 3:1 (since 1/4th was taken out) how is this calculated?

then solving for x give me 34 but how do i solve for x?

OPEN DISCUSSION OF THE FIRST QUESTION IS HERE: https://gmatclub.com/forum/how-many-gal ... 02888.html

OPEN DISCUSSION OF THE SECOND QUESTION IS HERE: https://gmatclub.com/forum/one-fourth-o ... 49134.html