Simple Equations for Real World Problems

In the 2012 Olympics, Usain Bolt won the 200-meter dash with a time of

19.32 seconds. Write and solve an equation to find his average speed

to the nearest hundredth of a meter per second.

What should we do first?

• Solve the Problem

• Make a plan

• Understand the problem

• Look back

Tags

CCSS.6.EE.B.7

In the 2012 Olympics, Usain Bolt won the 200-meter dash with a time of
19.32 seconds. Write and solve an equation to find his average speed
to the nearest hundredth of a meter per second.

So lets understand the question:
You know the winning time and the distance correct?
Using those 2 numbers we should be able to find his average speed to the nearest hundredth of a meter per second.

Lets Make a plan: Use the distance formula to write an equation that represents the problem.

Distance formula: Distance is equal to rate multiplied by time or
 $d=r\cdot t$  

So what is my equation?

•  $200=19.32\cdot t$  

•  $d=19.32\cdot200$  

•  $d=200\cdot19.32$  

•  $200=r\cdot19.32$  

Tags

CCSS.6.EE.B.7

In the 2012 Olympics, Usain Bolt won the 200-meter dash with a time of
19.32 seconds. Write and solve an equation to find his average speed
to the nearest hundredth of a meter per second.

Solve the Problem:

Now that we have an equation, what Property of Equality should we use to solve it?

 $200=r\cdot19.32$  

• Addition Property of Equality

• Subtraction Property of Equality

• Multiplication Property of Equality

• Division Property of Equality

Tags

CCSS.HSA.REI.A.1

In the 2012 Olympics, Usain Bolt won the 200-meter dash with a time of
19.32 seconds. Write and solve an equation to find his average speed
to the nearest hundredth of a meter per second.

Solve for r:

 $200=r\cdot19.32$  

• 10.35

• 3,864

• 180.68

• 219.32

Tags

CCSS.6.EE.B.7

In the 2012 Olympics, Usain Bolt won the 200-meter dash with a time of

19.32 seconds. Write and solve an equation to find his average speed

to the nearest hundredth of a meter per second.

Look Back:

If someone said that Usain Bolts average speed was about 10 seconds, is that reasonable based off of what we now know?

• Yes

• No

Tags

CCSS.6.EE.B.7

Suppose Usain Bolt ran 400 meters at the same average speed (10.35) that he ran the 200 meters. How long would it take him to run 400 meters? Round your answer to the nearest hundredth of a second (two decimal places).

Understand the Problem:

•  $d$  Distance

•  $r$ Rate 

•  $t$  Time

Tags

CCSS.HSF-LE.A.1B

Suppose Usain Bolt ran 400 meters at the same average speed (10.35) that
he ran the 200 meters. How long would it take him to run 400 meters?
Round your answer to the nearest hundredth of a second (two decimal places).

What would the new equation look like?
 $d=r\cdot t$  

•  $200=400\cdot t$  

•  $10.35=400\cdot t$  

•  $10.35=200\cdot t$  

•  $400=10.35\cdot t$  

Tags

CCSS.6.EE.B.7

 $400=10.35\cdot t$  Suppose Usain Bolt ran 400 meters at the same average speed (10.35) that
he ran the 200 meters. How long would it take him to run 400 meters?
Round your answer to the nearest hundredth of a second (two decimal places).

Solve:

• 4140

• 38.65

• 389.65

• 410.35

Tags

CCSS.6.EE.B.7

On January 22, 1943, the temperature in Spearfish, South Dakota, fell from 54°F at 9:00 a.m. to − 4°F at 9:27 a.m. How many degrees did the temperature fall?

Understanding the problem:

What are we being asked to do?

• Find the total amount of degrees the temperature changed

• Find the new temperature

• Find the starting temperature

Tags

CCSS.7.NS.A.1C

On January 22, 1943, the temperature in Spearfish, South Dakota, fell from 54°F at 9:00 a.m. to − 4°F at 9:27 a.m. How many degrees did the temperature fall?

• Temp. at 9:27 a.m. $=$ Temp. at 9:00 a.m. $-$ Number of degrees it fell

• Temp. at 9:00 a.m. $=$ Temp. at 9:27 a.m. $-$ Number of degrees it fell

• Number of degrees it fell $=$ Temp. at 9:00 a.m. $-$ Temp. at 9:27 a.m. Number of degrees it fell

• Number of degrees it fell $=$ Temp. at 9:27 a.m. Number of degrees it fellTemp. at 9:00 a.m. $-$ Temp. at 9:00 a.m.

Tags

CCSS.7.NS.A.1C