# Tutor profile: Eliana S.

## Questions

### Subject: Basic Math

Solve this equation: 9 - (4 +5) / 3 = ?

To solve this equation we'd need to use PEMDAS (parentheses, exponents, multiplication/division, addition/subtraction), which tells us the order in which we need to solve this equation. So the first thing we would look at are the parentheses, which is "(4+5)." Solving for that would give us 9, and our new equation would look like this: 9 - 9 / 3. The next in the list of PEMDAS is multiplication/division. So we'd look at "9 / 3" which gives us 3. Our equation will now read: 9 - 3. Then we just do this simple subtraction to get our final answer of 6!

### Subject: Chemistry

In a titration, 15.0 mL of 0.050 M HCl(aq) is exactly neutralized by 30.0 mL of KOH(aq) of unknown concentration. What is the concentration of the KOH(aq) solution?

In order to answer this question we'd use the equation: M1V1 = M2V2, where M=concentration and V=volume. M1 would be the concentration of HCl (aq) and would equal 0.050 M. V1 would be the volume of HCl (aq) and equal 15.0 mL. V2 would be the volume of KOH (aq) and equal 30.0 mL. We are solving for M2, the concentration of KOH (aq). We would just plug those numbers into the original equation: (0.050)*(15.0) = M2*(30.0). When you solve for M2 you get 0.025 M as the concentration for the KOH (aq) solution.

### Subject: Biology

In butterflies, the allele for patterned wings (P) is dominant, and the allele for unpatterned wings (p) is recessive. A butterfly breeder mates a homozygous dominant mother with a heterozygous male. What is the chance that the offspring will have patterned wings?

This is a question that would be best answered using a Punnett square. The genotype of the mother is PP (indicating two dominant alleles), while the genotype of the father is Pp (indicating one dominant, and one recessive allele). The Punnett square would show that offspring would have the following genotypes: PP, PP, Pp, and Pp. The only way to get the recessive phenotype of unpatterned wings would be to have a homozygous recessive genotype of pp. Because none of the offspring have that genotype, they would all have patterned wings, giving a 100% chance (or 4/4 chance) of the offspring having patterned wings.

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