Apatient needs to be given exactly 500 ml of a 5.0% (w/v) intravenous glucose solution. the stock solution is 35% (w/v). how many milliliters of the stock solution are needed to prepare the fluid for the iv bag?

In this question, the patient needs to be given exactly 500 ml of a 5.0%. The content of the glucose should be:
weight= volume * density* concentration
500ml * 1mg/ml *5%= 25mg.

The stock solution is 35%, then the amount needed in ml would be: 
weight= volume * density* concentration
25mg= volume * 1mg/ml *35%
volume= 25/35%= 500/7= 71.43ml

500bc indiais the answer.