A hot air balloon is descending vertically at a rate of $3\text{ ft/s}$. If there is a person standing $40\text{ ft}$ away from the point right below the balloon, how fast is the distance between the person and the balloon decreasing when the balloon is $30\text{ ft}$ above the ground?

• A. $0.8\text{ft/s}$
• B. $1.8\text{ft/s}$
• C. $2.8\text{ft/s}$
• D. $5\text{ft/s}$

Answer: (B)