## Question about alligation

by Cora
(Oak Park, CA, USA)

How many grams of petrolatum should you add to 30 g of hydrocortisone 2.5% ointment to reduce its strength to 2.0%? The percent strength of petrolatum is zero.

 Sep 04, 2011 The correct answer by: Keith Using an alligation for this one is possible. However, an Algebra equation is more practical.Here's the set-up30(0.025) = (30+X)(0.02)Do the math, and X = 7.5and Grams is the variable we were working with.Answer = 7.5 grams

 Sep 04, 2011 please provide the correct answer by: Anonymous I too calculated 7.5g to be the answer. Please provide the correct answer. Having comments is not useful unless we actually know the correct answer.

 Aug 16, 2011 tic tac toe? by: Anonymous 2.5 2 parts of 2.5% 20 0.5 parts of 0%2.5 total parts0.5/2.5= 0.20.2 x 30g= 6 grams

 Aug 06, 2011 NOT 0.25 by: Anonymous NOT USING ALLIGATION30*0.025= X*0.02.IT'S NOT 0.25

 Jul 09, 2011 I did not do a allegation. by: Anonymous IV*IS=FV*FS so 30g*.25=FV*.02 multiply 30*.25=7.5 then divide 7.5/.02 equals 375 grams of %2.0 so 375-30=345 add 345 grams

 May 28, 2011 Please check by: Anonymous I got 7.5 grams.Is this correct?

privacy