Rekha covers a distance of $$15\ \text{km}$$ walking with a speed of $$3\ \text{km/h}$$. How much distance would she cover in the same time, if she walks at a speed of $$7\ \text{km/h}$$?

A

$$35\ \text{km}$$

B

$$50\ \text{km}$$

C

$$30\ \text{km}$$

D

$$45\ \text{km}$$