Please help with this question.

20 da is equal to a. 2,000 cm. b. 2 m. c. 20,000 cm. d. 20,000 mm

How can i differentiate this equation?

If you invest 1,500 today in a bank that gives you a 5 percent annual interest rate, which of these items can you buy in two years? a. electronics worth $1,650 b.fitness equipment worth $1,700 c.a holiday package worth $2,000