Explanation

Start by translating her earnings on her shares of Capital Growth Fund were three times half of her earnings on her investment in Venture Index Fund from English to math. Represent her earnings in Capital Growth Fund as C. Were translates to “ = .” Three times half is “3 × \(\frac{1}{2}\),” and of is “×” (multiplication). Represent Melania’s earnings from Venture Index Fund as V,
and the resulting equation is

C =\(\frac{3}{2}V\).

Total earnings on the two funds were $1,250, so C + V = $1,250, and since C =\(\frac{3}{2}V\), that equation can be rewritten as

\(\frac{3}{2}V+V= 1250\) or \(\frac{5}{2}V = 1250\).

Solve this to find that V = $500 earned on Venture Index Fund. Notice that this is a partial answer that is included among the answer choices. Continuing to solve, represent the amount of money invested in Venture Index Fund as x. Melania had three times as much money invested in Capital Growth Fund as in Venture Index Fund; therefore she had 3x dollars invested in Capital Growth Fund. She had a total of $20,000 invested in the two funds; therefore \(3x + x = 20,000\). Solve to find that x = $5,000 invested in Venture Index Fund.

Now, plug in those numbers to the percent interest formula given in the problem, \((\frac{500}{5000})*100\), which equals the credited answer, choice (D), 10. You will arrive at the remaining, wrong answer choices if you mistakenly solve for the percent interest earned on Capital Growth Fund, and/or you represent your answer as a multiplier, rather than a percent (i.e., 0.01 versus 10%).

Hence option D is correct.