Academic common room
Help with a maths calculation
planningaheadtoday · 10/05/2020 16:46
I keep seeing the obvious but I know it's wrong.
My brother has a company and has received 5litres of hand sanitizer.
It is 2000ml softener mixed with 3000ml alcohol. It's 60% alcohol.
I'm trying to add alcohol (95%) to make it up to 70% volume as that's what he ordered but couldn't get.
How much alcohol should I add?
I thought it was around 500ml but my logical brain says no as the amount of softener is too much in the overall product.
What do you think? It's hurting my head!
satsumamumma · 11/05/2020 16:56
You should add two litres of alcohol. Then you will have 7 litres in total.
Of that, 3 litres is alcohol in the original supply.
Plus 95% of the extra 2 litres so 1900 ml alcohol.
Total alcohol 4900 out of 7000 is 70%
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