Nina is 10 years younger than Deepak. Deepak is 3 times as old as Nina. Which system of equations can be used to find d, Deepak's age, and n, Nina's age?

Since Nina is 10 years younger than Deepak, Deepak’s age is Nina’s age plus 10: d = n + 10. Deepak is also 3 times Nina’s age, so d = 3n. Together, these equations are choice A.

AI-written and checked against the verified answer.