Question

a city researcher wants to calculate the number of cars per hour that passed down main street during the summer festival. what information is needed to make the following calculation?
make conversion factor
cars passed per hour (cars/hr)
number of cars (cars)

carlos is in a band that has made some cds of their music. they have sold some of the cds and want to know how many remain. what information is needed to make the following calculation?
subtract
cds remaining (cds)
cds sold (cds)

sam runs a company that takes visitors on day long mountain hikes. each group of hikers must have a certain number of guides leading them. he wants to know how many guides he needs for tomorrow. what information is needed to make the following calculation?
guides per group (guides/group)
use conversion factor
guides (guides)

george works as a pilot and wants to determine his total flight time for the two flights he will pilot today. what information is needed to make the following calculation?
flight 1 time (hrs)
add
total flight time (hrs)

Explanation:

1. To find cars per hour, we use the formula $\text{Cars per hour} = \frac{\text{Total cars}}{\text{Time observed}}$, so we need the time period (in hours) over which the cars were counted.
2. To find remaining CDs, we use $\text{Remaining CDs} = \text{Total CDs made} - \text{CDs sold}$, so we need the total number of CDs the band made.
3. To find total guides, we use $\text{Total guides} = \text{Guides per group} \times \text{Number of groups}$, so we need the total number of hiker groups for tomorrow.
4. To find total flight time, we use $\text{Total flight time} = \text{Flight 1 time} + \text{Flight 2 time}$, so we need the duration of the second flight (in hours).

Answer:

1. Time period observed (hours)
2. Total number of CDs made (CDs)
3. Number of hiker groups (groups)
4. Flight 2 time (hrs)