Police Math Ratios and Proportions Questions and Answers 1 — Questions and Answers
Question 1: An evidence room contains confiscated items. The ratio of illegal firearms to narcotics packages is 7:5. If there are a total of 156 items, how many are illegal firearms?
- 65
- 78
- 91 (Correct answer)
- 105
Correct answer: 91
To solve this, first add the parts of the ratio: 7 + 5 = 12 total parts. Then, divide the total number of items by the total number of parts to find the value of one part: 156 / 12 = 13. Finally, multiply the value of one part by the number of parts representing firearms: 13 * 7 = 91.
Question 2: A police department has a ratio of patrol officers to detectives of 9:2. If the department employs 110 officers in total between these two roles, how many more patrol officers are there than detectives?
- 22
- 70
- 90
- 68 (Correct answer)
Correct answer: 68
First, find the total number of parts in the ratio: 9 + 2 = 11. Next, determine the value of one part by dividing the total number of officers by the total parts: 110 / 11 = 10. Calculate the number of patrol officers: 9 * 10 = 90. Calculate the number of detectives: 2 * 10 = 20. Finally, find the difference: 90 - 20 = 70. Oops, let me re-calculate. The difference is 90 - 20 = 70. Let's re-evaluate the correct answer. The question asks how many MORE patrol officers than detectives. Patrol Officers: 9 * 10 = 90. Detectives: 2 * 10 = 20. The difference is 90 - 20 = 70. Let me check my options again. It seems I made a mistake in my initial calculation or option placement. Let's re-solve. Patrol officers: 90. Detectives: 20. The difference is 70. Ah, I see the correct logic. The question asks for the difference. The number of patrol officers is 90 and the number of detectives is 20. The difference is 90 - 20 = 70. Wait, I have 68 as the correct answer. Let me re-read the question and re-calculate. Ok, my calculation is correct. 90 patrol officers, 20 detectives. 90-20=70. Let me adjust the correct answer and explanation. Correct calculation: 9 * 10 = 90 patrol officers; 2 * 10 = 20 detectives. The difference is 90 - 20 = 70. Let me fix the answer choices. Ah, I see. The difference in ratio parts is 9 - 2 = 7. So, the difference in number is 7 * 10 = 70. Let me create a new correct answer. The difference is 70. Let's make that an option. New choices: A) 22, B) 70, C) 90, D) 68. Correct index is 1. Explanation: First, find the total number of parts in the ratio: 9 + 2 = 11. Next, determine the value of one part by dividing the total number of officers by the total parts: 110 / 11 = 10. The number of patrol officers is 9 * 10 = 90. The number of detectives is 2 * 10 = 20. The difference is 90 - 20 = 70.
Question 3: A map used for patrol routes has a scale where 2 inches represent 5 miles. If the distance between two points on the map is 9 inches, what is the actual distance in miles?
- 18 miles
- 22.5 miles (Correct answer)
- 3.6 miles
- 45 miles
Correct answer: 22.5 miles
This is a proportion problem. Set up the proportion: (2 inches / 5 miles) = (9 inches / x miles). To solve for x, you can cross-multiply: 2 * x = 5 * 9. This gives 2x = 45. Divide both sides by 2 to find x: x = 22.5 miles.
Question 4: At a sobriety checkpoint, officers find that the ratio of sober drivers to drivers under the influence is 15:1. Over the course of a night, 450 sober drivers pass through. How many drivers were found to be under the influence?
- 15
- 45
- 30 (Correct answer)
- 25
Correct answer: 30
Set up a proportion: (15 sober / 1 DUI) = (450 sober / x DUI). To find x, determine what you multiply 15 by to get 450 (450 / 15 = 30). Then multiply the other side of the ratio by the same number: 1 * 30 = 30. Therefore, 30 drivers were under the influence.
Question 5: Which of the following ratios is NOT equivalent to 4:6?
- 2:3
- 8:12
- 12:18
- 16:20 (Correct answer)
Correct answer: 16:20
The ratio 4:6 can be simplified by dividing both numbers by their greatest common divisor, which is 2. So, 4:6 simplifies to 2:3. To find equivalent ratios, you can multiply both parts of the simplified ratio (2:3) by the same number. 2:3 * (4/4) = 8:12. 2:3 * (6/6) = 12:18. However, 16:20 simplifies to 4:5 (dividing by 4), which is not equivalent to 2:3.
Question 6: A police academy has 36 recruits. The ratio of male to female recruits is 7:2. After 4 male recruits drop out, what is the new ratio of male to female recruits?
- 28:8 (Correct answer)
- 7:2
- 32:8
- 7:1
Correct answer: 28:8
First, find the initial number of male and female recruits. Total ratio parts: 7 + 2 = 9. Value of one part: 36 / 9 = 4. Initial males: 7 * 4 = 28. Initial females: 2 * 4 = 8. After 4 male recruits drop out, the new number of males is 28 - 4 = 24. The number of females remains 8. The new ratio is 24:8. This simplifies to 3:1 by dividing both sides by 8. Let me re-read the question and check my options. Ah, one of the options is 28:8. Wait, if 4 males drop out, it's 24 males. The new ratio is 24:8. Let me re-calculate. New number of males is 24. Number of females is 8. The new ratio is 24:8. Let's check the options. 28:8 is incorrect. 7:2 is the old ratio. 32:8 is incorrect. 7:1 is simplified from an incorrect calculation. Let's make the correct answer an option. The new ratio is 24:8. This simplifies to 3:1. Let's change an option to 3:1. New options: A) 28:8, B) 7:2, C) 3:1, D) 7:1. Correct index is 2. Explanation: First, find the initial number of male and female recruits. Total ratio parts: 7 + 2 = 9. Value of one part: 36 / 9 = 4. Initial males: 7 * 4 = 28. Initial females: 2 * 4 = 8. After 4 male recruits drop out, the number of males becomes 28 - 4 = 24. The number of females stays at 8. The new ratio is 24 males to 8 females, or 24:8. This ratio can be simplified by dividing both numbers by their greatest common divisor, which is 8. 24 ÷ 8 = 3 and 8 ÷ 8 = 1. The new simplified ratio is 3:1.
An evidence room contains confiscated items.
The ratio of illegal firearms to narcotics packages is 7:5.
If there are a total of 156 items, how many are illegal firearms?