Question

Beaker A contains 1 liter which is 15 percent oil and the rest is vinegar, thoroughly mixed up. Beaker B contains 2 liters which is 55 percent oil and the rest vinegar, completely mixed up. Half of the contents of B are poured into A, then completely mixed up. How much oil should now be added to A to produce a mixture which is 60 percent oil

Answer 1

Add 1.25 litres of oil.

Explanation:

Contents in beaker A implies;

15% of oil in 1 litre = 0.15 litres of oil

So that, there are 0.15 litres of oil and 0.85 litres of vinegar in beaker A.

Contents in beaker B implies:

55% of oil in 2 litres = 1.1 litres of oil

So that, thee are 1.1 litres of oil and 0.9 litres of vinegar in beaker B.

Half of contents of B poured into A implies that beaker A now contains:

0.15 litres + 0.55 litres = 0.7 litres of oil

0.85 litres + 0.45 litres = 1.3 litres of vinegar

The percentage of oil in A now =
`(0.7)/(2)` x 100%

= 35%

To increase the percentage of oil to 60%, then:

0.7 litres + 1.25 litres = 1.95 litres of oil

But the new total litres of the content in beaker A = 3.25 litres

So that;

`(1.95)/(3.25)` x 100% = 60%

Therefore, to produce a mixture which is 60% oil, add 1.25 litres of oil.