Which matrix multiplication is possible?

Find the given elements if matrix d:

Maria donates a fixed amount, a, to a charity each month. if she donates $300 in 12 months, what is the equation for a? a. a + 300 = 12 b. a × 300 = 12 c. a × 12 = 300 d. a + 12 = 300 e. a + 32 = 100

Julia is going for a walk through the neighborhood. what unit of measure is most appropriate to describe the distance she walks?