| Your Results | Global Average | |
|---|---|---|
| Questions | 5 | 5 |
| Correct | 0 | 3.31 |
| Score | 0% | 66% |
A sports card collection contains football, baseball, and basketball cards. If the ratio of football to baseball cards is 9 to 2 and the ratio of baseball to basketball cards is 9 to 1, what is the ratio of football to basketball cards?
| 3:6 | |
| 81:2 | |
| 5:4 | |
| 1:1 |
The ratio of football cards to baseball cards is 9:2 and the ratio of baseball cards to basketball cards is 9:1. To solve this problem, we need the baseball card side of each ratio to be equal so we need to rewrite the ratios in terms of a common number of baseball cards. (Think of this like finding the common denominator when adding fractions.) The ratio of football to baseball cards can also be written as 81:18 and the ratio of baseball cards to basketball cards as 18:2. So, the ratio of football cards to basketball cards is football:baseball, baseball:basketball or 81:18, 18:2 which reduces to 81:2.
How many hours does it take a car to travel 175 miles at an average speed of 35 miles per hour?
| 6 hours | |
| 1 hour | |
| 5 hours | |
| 8 hours |
Average speed in miles per hour is the number of miles traveled divided by the number of hours:
speed = \( \frac{\text{distance}}{\text{time}} \)Solving for time:
time = \( \frac{\text{distance}}{\text{speed}} \)
time = \( \frac{175mi}{35mph} \)
5 hours
How many 7-passenger vans will it take to drive all 74 members of the football team to an away game?
| 11 vans | |
| 4 vans | |
| 3 vans | |
| 9 vans |
Calculate the number of vans needed by dividing the number of people that need transported by the capacity of one van:
vans = \( \frac{74}{7} \) = 10\(\frac{4}{7}\)
So, it will take 10 full vans and one partially full van to transport the entire team making a total of 11 vans.
Convert 0.0005803 to scientific notation.
| 5.803 x 104 | |
| 5.803 x 10-5 | |
| 5.803 x 10-4 | |
| 58.03 x 10-5 |
A number in scientific notation has the format 0.000 x 10exponent. To convert to scientific notation, move the decimal point to the right or the left until the number is a decimal between 1 and 10. The exponent of the 10 is the number of places you moved the decimal point and is positive if you moved the decimal point to the left and negative if you moved it to the right:
0.0005803 in scientific notation is 5.803 x 10-4
A machine in a factory has an error rate of 7 parts per 100. The machine normally runs 24 hours a day and produces 9 parts per hour. Yesterday the machine was shut down for 6 hours for maintenance.
How many error-free parts did the machine produce yesterday?
| 138 | |
| 114 | |
| 76 | |
| 150.7 |
The hourly error rate for this machine is the error rate in parts per 100 multiplied by the number of parts produced per hour:
\( \frac{7}{100} \) x 9 = \( \frac{7 \times 9}{100} \) = \( \frac{63}{100} \) = 0.63 errors per hour
So, in an average hour, the machine will produce 9 - 0.63 = 8.37 error free parts.
The machine ran for 24 - 6 = 18 hours yesterday so you would expect that 18 x 8.37 = 150.7 error free parts were produced yesterday.