A: The intensity of the light at 20 feet from the source is 60 - 15 = 45 candles. The answer is (A).
Answer the following multiple choice question with options (a), (b), (c), (d), (e).
Q: John found that the average of 15 numbers is 40. If 10 is added to each number then the mean of the numbers is? Answer Choices: (a) 50 (b) 45 (c) 65 (d) 78 (e) 64 
A: The answer is (a). 

Answer the following multiple choice question with options (a), (b), (c), (d), (e).
Q: If a / b = 3/4 and 8a + 5b = 22,then find the value of a. Answer Choices: (a) 1/2 (b) 3/2 (c) 5/2 (d) 4/2 (e) 7/2 
A: The answer is (b). 

Answer the following multiple choice question with options (a), (b), (c), (d), (e).
Q: A person is traveling at 20 km/hr and reached his destiny in 2.5 hr then find the distance? Answer Choices: (a) 53 km (b) 55 km (c) 52 km (d) 60 km (e) 50 km 
A: The answer is (e). 

Answer the following multiple choice question with options (a), (b), (c), (d), (e).
Q: How many keystrokes are needed to type the numbers from 1 to 500? Answer Choices: (a) 1156 (b) 1392 (c) 1480 (d) 1562 (e) 1788 
A: The answer is (b).

Answer the following multiple choice question with options (a), (b), (c), (d), (e).
For a light that has an intensity of 60 candles at its source, the intensity in candles, S, of the light at a point d d feet from the source is given by the formula S=60k/d^2 60, where k is a constant. If the intensity of the light is 15 candles at a distance of 2 feet from the source, what is the intensity of the light at a distance of 20 feet from the source? Answer Choices: A)3/20 candles B)1/2 candles C)1 1/3 candles D)2 candles E)3 candles