Final answer:
The scientist uses 13/30 of a full bottle of solution for the experiment.
Step-by-step explanation:
To find out how much of a full bottle of solution the scientist uses, we need to subtract the amount used from the original amount in the bottle. The bottle is currently 5/6 full, so we can represent this as a fraction: 5/6. The scientist uses 2/5 of the solution, so we can represent this as another fraction: 2/5. To find out how much of a full bottle the scientist uses, we need to subtract 2/5 from 5/6 using fraction subtraction.
Step 1: Find a common denominator for the fractions. The least common multiple of 6 and 5 is 30, so we can rewrite the fractions as 25/30 and 12/30.
Step 2: Subtract the fractions. 25/30 - 12/30 = 13/30.
Therefore, the scientist uses 13/30 of a full bottle of solution for the experiment.