By weight, liquid A makes up 8 percent of solution R and 18 percent of

Question

By weight, liquid A makes up 8 percent of solution R and 18 percent of solution S. If 3 grams of solution R are mixed with 7 grams of solution S, then liquid A accounts for what percent of the weight of the resulting solution?

A. 10%
B. 13%
C. 15%
D. 19%
E. 26%

Show Answer

Official Answer

C

A. 10%
B. 13%
C. 15%
D. 19%
E. 26%

carcass · Answer

Would be wise BEFORE to post a question make a quick search on the forum to see if the question is already discussed or not, without creating a duplicate post even though this is the GRe section.

Here, it would be best to post only questions for the GRE or problem-solving from the GMAT that are not already discussed on the forum.

Either way, the question is located here https://gmatclub.com/forum/by-weight-li ... l#p2094841

regards

Sajjad1994 · Answer

Official Explanation

Liquid A makes up 8 percent of the weight of solution R and 18 percent of the weight of solution S. Therefore, 3 grams of solution R contain (0.08)(3), or 0.24 gram of liquid A, and 7 grams of solution S contain (0.18)(7), or 1.26 grams of liquid A. When the two solutions are mixed, the resulting solution weighs 3 + 7, or 10 grams and contains 0.24 + 1.26, or 1.5 grams of liquid A. This means that liquid A makes up 1.5/10, or 15/100, or 15 percent of the weight of the resulting solution.

The correct answer is Choice C.

By weight, liquid A makes up 8 percent of solution R and 18 percent of

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards