Which of Mendel's laws or principles explains that traits are passed from parents to offspring individually instead of as pairs, groups, or sets?

Law of independent assortment.

Explanation:

Mendel's law of independent assortment states that genes do not influence each other while they are sorted into alleles.

Every possible gene is likely to occur. This means that the traits are passed from one generation to another generation individually not in pair of allele, sets or groups.

The characters are represented individually not in pair. Though the characters are present in pair but they are individually represent themselves and do not affect each other.

9.9 years

a = p(1 + rt) . . account balance after time t at rate r starting with principal p

3000 = 2500(1 + 0.0202t) . . filling in the given numbers

1.2 = 1 + 0.0202t . . divide by 2500

0.2 = 0.0202t . . . subtract 1

0.2/0.0202 = t ≈ 9.901

it will take about 9.9 years for the account balance to reach $3000.