I am after some help with a simple formular, kind of embaresing actually, but here goes.

An example of the question:

If you have a bottle of 70% orange juice (presumed 30% water I spose)

And you want to make a 100ml drink that has 27% OJ, how much of the orignal would you put in.

My attemps come up with different answers !!!!

This must be a simple answer I am sure !!! Any takers ?

Simplify the problem first.

If you had 100% OJ, then you would use 27ml to get the wanted percentage. But as the OJ is only 70%, you obviously need a bit more.

Divide the 27ml by 0.70, which gives the answer 38.6ml of orange juice.

I'm not a mathematician, so no guarantees that the answer is correct

I think that's right.

Another way to look at it simply is 27ml is 70% of what?....ie 38.57 (essentially the same as above).

Thus 38.6 ml of 70% OJ will produce 27% OJ if diluted to 100 ml.

Buy two bottles and have a bit extra.

Thanks

If you have a bottle of 70% orange juice (presumed 30% water I spose)

And you want to make a 100ml drink that has 27% OJ, how much of the orignal would you put in

I believe the 30% would be Vodka, not water. In which case 27% OJ is about right. A tad on the weak side. Just my personal preference.