๐ Distance formula d=rt (11 MCQs)
๐ From Digital SAT Algebra โข 2. Linear Equations And Inequalities โข 11 questions available
What is Distance formula d=rt?
Definition:
The distance formula relates distance , rate (speed) , and time . It states that distance equals the product of rate and time. This formula is used to solve motion problems where one of the three variables is unknown.
Working:
To find rate, solve ; to find time, solve . For example, if a car travels 150 miles in 3 hours, , , so mph.
Example:
A train travels 240 miles at a speed of 60 mph. Find the time. Using , , divide by 60: hours.
Reason:
This formula is a fundamental real-world application of linear equations, allowing calculation of distance, speed, or time when two are known.
๐ All Distance formula d=rt MCQs
Q1. A cyclist travels at km/h for hours. Which expression correctly models the distance traveled before calculating the answer?
๐ Explanation: The distance is found by multiplying rate by time, so . The other operations confuse the roles of rate and time and therefore do not represent the physical situation correctly.
Q2. Two buses leave the same terminal at the same time. Bus A travels at km/h and Bus B at km/h. After hours, how much farther has Bus B traveled?
๐ Explanation: Bus A travels km, while Bus B travels km. Their difference is km. Comparing both distances prevents the common error of using only one rate.
Q3. A delivery driver must travel km. If the average speed is km/h, which reasoning correctly determines the travel time?
๐ Explanation: Starting with , solving for time gives . Therefore hours. Multiplying distance and rate produces incorrect units, while reversing the division gives hours per kilometer instead of hours.
Q4. A student says that traveling km/h for hours gives km because . What is the best analysis of the student's error?
๐ Explanation: The student's mistake is treating rate and time as quantities that can simply be added. A rate of km/h means kilometers are covered each hour, so four hours produce km.
Q5. A car travels km in the first hours and then km in the next hours. What is its average rate for the entire trip?
๐ Explanation: The total distance is km and the total time is hours. Thus the average rate is km/h. Averaging the two rates directly would ignore unequal time intervals.
Q6. A distance-versus-time graph shows a straight line passing through and , where time is measured in hours and distance in kilometers. What does the slope represent?
๐ Explanation: For a distance-versus-time graph, slope equals change in distance divided by change in time. Here the slope is km/h, so it represents the constant travel rate rather than total distance or elapsed time.
Q7. A runner increases speed from m/s to m/s while keeping the running time fixed at seconds. By how much does the distance increase?
๐ Explanation: At m/s for seconds, the runner covers m. At m/s for the same time, the distance is m. The increase is m, showing how distance changes proportionally with rate when time is fixed.
Q8. A student calculates the time for a -km trip at km/h as hours by multiplying . Which correction best explains why this is wrong?
๐ Explanation: Since , isolating time requires division: . Therefore hours. The product has units of kilometers squared per hour, which cannot represent a time measurement.
Q9. Two distance-time graphs are straight lines from the origin. Graph A reaches km at hours, while Graph B reaches km at hours. Which conclusion is correct?
๐ Explanation: The slope gives the rate. Graph A has rate km/h, while Graph B has rate km/h. Therefore Graph B is steeper and represents the faster traveler despite having a smaller displayed distance.
Q10. A train travels km at km/h, stops for minutes, and then travels another km at km/h. What is the train's total elapsed time, including the stop?
๐ Explanation: The first segment takes hours and the second takes hours. Adding the -hour stop gives hours. Thus the correct choice is hours, not hours, because elapsed time includes the stop.
Q11. A vehicle must cover km in hours. It spends hour stopped, so it can travel for only hours. What constant travel rate is required while the vehicle is moving?
๐ Explanation: The available moving time is hours. Using , the required rate is km/h. Using all six hours would incorrectly ignore the stop and underestimate the necessary moving speed.