Solving Speed Problems

Solving Speed Problems

I can use the formula

 $Speed\ =\frac{Dis\tan ce}{Time}$  to solve real world problems.

Setting up speed problems using equivalent ratios (NOT conversion factors)

• Set up the ratio with the information you know using the formula

   $Speed\ =\frac{dis\tan ce}{time}$  

• Set up the equivalent ratio for the unknown information with the same measurement units in the numerator and denominator as the 1st ratio

Using division to find equivalent ratios

• Follow the same steps to set up the problem.

• Use division to find the equivalent ratio and to solve the problem.

Multiple Choice

Madie drove 200 miles at a speed of 50 miles per hour. Which equation will help you find the number of hours she was driving?

• $\frac{50\ miles}{1\ hour}=\frac{200\ miles}{?\ hours}$

• $\frac{50\ miles}{1\ hour}=\frac{?}{200\ miles}$

• $\frac{200\ miles}{1\ hour}=\frac{50\ miles}{?\ hours}$

• $\frac{200\ miles}{1\ hour}=\frac{?\ hours}{50\ miles}$

Multiple Choice

Marvin rides his bike at an average speed of 13 miles per hour. How far can he bike in 8 hours?

• 104 miles

• 1.625 miles

• 21 miles

• 7 miles

Multiple Choice

Irwin rode his bicycle from one end of the trail and back at a speed of 20 miles per hour. If the trail is 4 miles long, for how many hours was Irwin riding?

• 0.2 hours

• 0.4 hours

• 2.5 hours

• 5.0 hours

Find Time when you are given speed and distance

• Use the speed formula

   $Speed\ =\frac{Dis\tan ce}{Time}$  

• Set up the ratio with the information given

• Set up an equivalent ratio with distance you know over the time you are trying to find

• Keep the ratios equivalent by multiplying or dividing the numerator and the denominator by the same number.

Multiple Choice

How long does it take an airplane flying at a speed of 600 miles per hour to fly 3000 miles? Hint:

 $Speed\ =\frac{dis\tan ce}{time}$  

• 0.2 hours

• 0.5 hours

• 2 hours

• 5 hours

Find Distance when you are given speed and time.

• Use the speed formula
  

   $Speed\ =\frac{dis\tan ce}{time}$  

• Set up the ratio with the information given

• Set up an equivalent ratio with time  you know under the distance you are trying to find

• Keep the ratios equivalent by multiplying or dividing the numerator and the denominator by the same number.

Multiple Choice

What is the missing distance?

• 39 meters

• 31 meters

• 140 meters

• 8.75 meters

Comparing Speeds

• Identify each ones rate of speed

• Convert each one to a unit rate of speed

• Compare the unit rates of speed

• If the rates of speed have the same numerator or denominator you can just compare the other

Multiple Select

Mel drove 230 miles in 4 hours, and Pia drove 230 miles in 5 hours. Without making any calculations, who drove faster? (Click all that apply)

• Mel drove faster than Pia

• They drove the same time

• It took Mel less time to drive the same distance as Pia, so he drove faster

• $230\ \div4\ \ >\ 230\ \div\ 5$

Multiple Choice

Two sailboats had a race. Sailboat A traveled 40 feet every 5 seconds, and Sailboat B traveled 56 feet every 8 seconds. Which sailboat won the race, and how fast was it going?

• Sailboat A won the race, and it was going 7 feet per second

• Sailboat A won the race, and it was going 8 feet per second

• Sailboat B won the race, and it was going 7 feet per second

• Sailboat B won the race, and it was going 8 feet per second