Question wasn't clear, but I hope this helps!
Lemon Squash If you put 90ml of concentrate in a glass, how
2 parts concentrate water should be added?
to 5 parts water x ml.
Ratio: 2:5 or 2/5
Now, if this ratio is maintained then the amount of water to be added to 90 ml concentrate in a glass can be calculated as:
2/5 = 90/x ( x = the unit (ml)/ how many ml of water)
Cross multiplication of the above equation will give us:
2x = 90 x 5 = 450
Dividing both sides by 2 we will get:
x = 450/2 = 225
Therefore, if we put 90ml of concentrate in a glass, the amont of water to be added is 225ml.
I hope this answer helps!
Yours Faithfully,
Damian. / Bright_SCR.