If you mix 30 gm 5% lidocaine cream and 90gm of 0.5% hydrocortisone cream, what percent of lidocaine and hydrocortisone do you have as the end product?

If you mix 30 gm 5% lidocaine cream and 90gm of 0.5% hydrocortisone cream, what percent of lidocaine and hydrocortisone do you have as the end product?
A . Lidocaine/Hydrocortisone 2%/1.25%
B . Lidocaine/Hydrocortisone 0.375%/0.15%
C . Lidocaine/Hydrocortisone 1.25 %/ 0.15%
D . Lidocaine/Hydrocortisone 2% /0.25%
E . Lidocaine/Hydrocortisone 1.25% /0.375%

View Answer

Answer: E

Explanation:

Lidocaine: 30g × 0.05 = 1.5g. Hydrocortisone: 90g × 0.005 = 0.45g. 90g + 30g = 120g. 1.5g/120g = 0.0125 × 100 = 1.25% Lidocaine. 0.45g/120g = 0.00375 × 100 = 0.375% Hydrocortisone.