Final answer:
Dilbert earned $480 in interest over 3 years by investing $4,000 at a 4% simple interest rate.
Step-by-step explanation:
how much interest did Dilbert earn over 3 years when he invested $4,000 at a 4% simple interest rate. The calculation for simple interest is Interest = Principal × Rate × Time. Let's calculate the interest: Interest = $4,000 × 4% × 3 years, Interest = $4,000 × 0.04 × 3, Interest = $160 × 3, Interest = $480. Therefore, Dilbert earned $480 in interest over the 3-year period. This means that over the 3-year period, Dilbert gained $480 in interest from his $4,000 investment. This straightforward calculation demonstrates the increase in value due to the simple interest rate applied to the initial investment.