Problem
Gas is escaping from a spherical balloon at a constant rate of 2 ft³/min. How fast, in ft²/min, is the outer surface area of the balloon shrinking when the radius is 12 ft?

Problem
Determine the percentage uncertainty in the area of a square that is 6.08 ± 0.01 m on a side.

Problem
In still water, your small boat averages 8 miles per hour. It takes you the same amount of time to travel 15 miles downstream, with the current, as 9 miles upstream, against the current. What is the rate of water's current?

Problem
\$180,000 was spent on the project that yields annual benefit of \$60,000 for a period of 8 years without any salvage value. Determine the benefit-to-cost ratio considering the cost of money to be 7%.

Problem
Which of the following pizzas is a better buy: a large pizza with 16-inch diameter for \$15 or a medium pizza with an 8-inch diameter for \$7.50? What is the cost per square inch of the better pizza?

Problem
Given the following equations:

$$ab = 1/8 \qquad ac = 3 \qquad bc = 6$$

Find the value of $a + b + c$.

Problem
Which of the following is the derivative with respect to x of $(x + 1)^3 - x^3$?

Problem
How many terms from the progression 3, 5, 7, 9, ... must be taken in order that their sum will be 2600?