Solve the variation problem.The intensity I of light varies inversely as the square of the distance D from the source. If the intensity of illumination on a screen 5 feet from a light is 4 foot candles, find the intensity on a screen 20 ft from the light.
A. 2 foot-candles
B. 1
foot-candles
C. 
foot-candles
D. 
foot-candles
Answer: D
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Use the laws of exponents to simplify each expression using positive exponents only. Assume all variables represent nonzero real numbers.4-3 ? 4
A. 64
B. 
C. 16
D. 
Solve.Linda and Dave leave simultaneously from the same starting point biking in opposite directions. Linda bikes at 5 miles per hour and Dave bikes at 10 miles per hour. How long will it be until they are 22 miles apart from each other?
A. 
hr
B. 1
hr
C. 4
hr
D. 
hr
Solve the variation problem.The distance it takes to stop a car varies directly as the square of the speed of the car. If it takes 112 feet for a car traveling at 40 miles per hour to stop, what distance is required for a speed of 
per hour?
A. 216 feet B. 264.3 feet C. 252 feet D. 252.34 feet
Use the formula for the sum of the first n terms of a geometric sequence to solve.Find the sum of the first 9 terms of the geometric sequence: -5, -10, -20, -40, -80, . . . .
A. -2553 B. -2518 C. -2555 D. -2575