# Tutor profile: Joseph Raymund E.

## Questions

### Subject: SAT II Mathematics Level 2

A skateboarder competing needs a mean of 7.2 (out of a total 8.0) to win the first-place medal. If there are three judges and one of them gives her a 5.5, what is the lowest score she can get from the remaining two judges if she still wants to finish first?

Her average needs to be 7.2. Since the formula for average is (score 1 + score 2 + score 3)/3, we can say (sum of the two scores + 5.5)/3 = 7.2 (multiplying both sides by 3) sum of the two scores + 5.5 = 21.6 (subtract 5.5 on both sides) sum of two scores = 16.1 (divide by two) 8.05 this is the lowest score she can get on a judge, and 16.1 combined, if she still wishes to be first place.

### Subject: Basic Chemistry

Explain why acetic acid is a much stronger acid than ethanol in water. Acetic Acid CH3COOH Ethanol CH3CH2OH

The conjugate acid of acetic is stabilized by the delocalized π electrons. Also, acetic acid has more oxygen, which have electron withdrawing properties.

### Subject: Biology

As pertains to evolution: Absorption spectra of plants or photosynthetic organisms show a very high absorbance on all spectrums and a very low absorbance on green. However, photosynthetic bacteria at the deeper layers of the oceans typically have high absorption primarily in the blue/violet range. Evolutionarily, how has this phenomena developed over time and what were the selecting factors?

Typically, only the blue and violet wavelengths of sunlight can penetrate the deepest layers of the oceans. With this in mind, there is selective pressure that gives advantages to organisms capable of doing photosynthesis with these wavelengths. By selecting them, their population frequency increases, until over time, the entire genome has that trait.

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