1. The first problem asks: What is fifteen times four? 2. The formula for multiplication is $a \times b = c$, where $a$ and $b$ are numbers and $c$ is their product. 3. Multiply 15 by 4: $$15 \times 4 = 60$$ 4. So, the answer is d. Sixty. 5. The second problem asks: What is $\frac{20}{20} \times \frac{9}{10}$? 6. The rule for multiplying fractions is: $$\frac{a}{b} \times \frac{c}{d} = \frac{a \times c}{b \times d}$$ 7. Apply this rule: $$\frac{20}{20} \times \frac{9}{10} = \frac{20 \times 9}{20 \times 10} = \frac{180}{200}$$ 8. Simplify the fraction $\frac{180}{200}$ by dividing numerator and denominator by 20: $$\frac{180 \div 20}{200 \div 20} = \frac{9}{10}$$ 9. So, the answer is b. $\frac{9}{10}$. Final answers: - Question 41: d. Sixty - Question 42: b. $\frac{9}{10}$