A 70% concentration of isopropyl alcohol is often used as a disinfectant for medical equipment such as thermometers and stethoscopes. The initial volume of 90% isopropyl alcohol needed to produce a batch of 70% isopropyl alcohol can be calculated using the following formula: (90%)(initial volume) = (70%)(final volume)
How many millimeters of 90% isopropyl alcohol are needed to create 1 liter of 70% isopropyl alcohol?
A. 0.00129 mL
B. 0.78 mL
C. 1.29 mL
D. 780 mL

Question

A 70% concentration of isopropyl alcohol is often used as a disinfectant for medical equipment such as thermometers and stethoscopes. The initial volume of 90% isopropyl alcohol needed to produce a batch of 70% isopropyl alcohol can be calculated using the following formula: (90%)(initial volume) = (70%)(final volume)
How many millimeters of 90% isopropyl alcohol are needed to create 1 liter of 70% isopropyl alcohol? 
A. 0.00129 mL
B. 0.78 mL
C. 1.29 mL
D. 780 mL

welshfella · Answer

0.90x = 0.70*1
x = 0.70/90 l
=  0.78 l
or 780 ml

aaron96 · Answer

thank you welshfella