BMST - Basic Math and Science Ratios, Proportions, and Percentages Questions and Answers — Questions and Answers
Question 1: A chemical solution contains acid and water in a ratio of 4:5. If the total volume of the solution is 72 liters, what is the volume of acid in the solution?
- 40 liters
- 32 liters (Correct answer)
- 36 liters
- 45 liters
Correct answer: 32 liters
The ratio of acid to water is 4:5. This means there are 4 + 5 = 9 parts in total. To find the volume of one part, divide the total volume by the total number of parts: 72 liters / 9 parts = 8 liters per part. The volume of acid is 4 parts, so 4 parts * 8 liters/part = 32 liters.
Question 2: A new machine can produce 150 widgets in 6 minutes. If the machine maintains this constant rate, how many widgets can it produce in one hour?
- 900
- 1200
- 1500 (Correct answer)
- 3000
Correct answer: 1500
This is a proportion problem. First, find the rate per minute: 150 widgets / 6 minutes = 25 widgets per minute. Since there are 60 minutes in an hour, multiply the per-minute rate by 60: 25 widgets/minute * 60 minutes/hour = 1500 widgets.
Question 3: A laboratory sample initially weighed 120 grams. After a dehydration process, its weight was reduced to 96 grams. What was the percentage decrease in the weight of the sample?
- 24%
- 25%
- 15%
- 20% (Correct answer)
Correct answer: 20%
To find the percentage decrease, first calculate the amount of weight lost: 120 grams - 96 grams = 24 grams. Then, divide the amount of decrease by the original weight and multiply by 100: (24 / 120) * 100 = 0.20 * 100 = 20%.
Question 4: A technician is preparing a saline solution. Which of the following represents the highest concentration of salt?
- 15 grams of salt in 100 grams of water
- 10 grams of salt in 50 grams of water (Correct answer)
- 25 grams of salt in 150 grams of water
- 5 grams of salt in 30 grams of water
Correct answer: 10 grams of salt in 50 grams of water
To compare the concentrations, calculate the percentage of salt for each option. A) 15/115 ≈ 13.0%. B) 10/60 ≈ 16.7%. C) 25/175 ≈ 14.3%. D) 5/35 ≈ 14.3%. The highest concentration is 10 grams of salt in 50 grams of water (which is a total solution of 60 grams). Alternatively, simplify the ratios: A) 3:20, B) 1:5 or 4:20, C) 1:6, D) 1:6. The ratio 1:5 is the highest concentration of salt.
Question 5: In a manufacturing plant, 60% of the employees are machine operators. Of the remaining employees, 25% are in maintenance. If there are 120 employees in maintenance, what is the total number of employees in the plant?
- 800
- 1200
- 1000 (Correct answer)
- 600
Correct answer: 1000
If 60% are operators, then 100% - 60% = 40% of employees are not operators. The maintenance staff is 25% of this remaining 40%. So, maintenance staff represents 0.25 * 40% = 10% of the total employees. If 120 employees represent 10% of the total, we can set up the equation 0.10 * Total = 120. Solving for Total gives Total = 120 / 0.10 = 1200 employees.
Question 6: The ratio of two numbers is 3:7. If 9 is added to each number, the new ratio becomes 12:23. What is the smaller of the original numbers?
- 10 (Correct answer)
- 15
- 25
- 8
Correct answer: 10
The ratio of boys to girls is 5:3, meaning there are 5+3=8 total parts. The total number of students is 40. So, one part is equal to 40 / 8 = 5 students. The number of boys is 5 parts * 5 students/part = 25. The number of girls is 3 parts * 5 students/part = 15. The difference is 25 - 15 = 10.
BMST - Basic Math and Science Ratios, Proportions, and Percentages Questions and Answers
A chemical solution contains acid and water in a ratio of 4:5.
If the total volume of the solution is 72 liters, what is the volume of acid in the solution?