Saturday, March 10, 2007

"QUESTION ON DEMAND"

26. How many ounces of water must be added to
a 30-ounce solution that is 40 percent
alcohol to dilute the solution to 25 percent
alcohol?
(A) 9
(B) 10
(C) 15
(D) 16
(E) 18

contributed by DEEPTI CHABBRA
Posted by at

3 comments:

goyalakshay said...

E. 18

March 10, 2007 at 10:16 AM
Unknown said...

E

March 11, 2007 at 12:20 AM
Admin said...

Let x be the amount of water added. Since there is no alcohol in the water, the percent of alcohol in the
water is 0%x. The amount of alcohol in the original solution is 40%(30), and the amount of alcohol in the
final solution will be 25%(30 + x). Now, the concentration of alcohol in the original solution plus the
concentration of alcohol in the added solution (water) must equal the concentration of alcohol in the resulting
solution:
40%(30) + 0%x = 25%(30 + x)
Multiplying this equation by 100 to clear the percent symbol yields
40(30) + 0 = 25(30 + x)
1200 = 750 + 25x
450 = 25x
18 = x
The answer is (E).

CORRECT MR MANIAC AND ANUMOLU

March 14, 2007 at 11:49 AM

Post a Comment

Subscribe to: Post Comments (Atom)