Standard MG 1.3  

  Use measures expressed as rates (e.g., speed, density) and measures expressed as products (e.g., person-days) to solve problems; check the units of the solutions; and use dimensional analysis to check the reasonableness of the answer. 

Student-Friendly Language

 I know how to use rates such as speed and density and measures expressed as products such as person-days to solve problems. I can also label correctly and check the reasonableness of the answer.

Example Problem

Alec and Fareen need to drive to Colin's house for a party. It will take them 2 hours to get to Colin's house from Fareen's house. If Alec drives at a speed of 25 miles per 30 minutes, how far away is Colin's house?

Step 1. Multiply 25 miles and 30 minutes by 2 to double the minutes and have 1 hour

 25·2 = 50 miles 

  30·2 =  60 minutes

Step 2. Use the formula t(s)=d to find your answer

t(s)=d

Time= 2 hours

Speed= 50 miles

2(50)=100

Answer: Colin's house is 100 miles away from Fareen's house.

Voicethread Example 

Links for Standard MG 1.3

Click HERE for Help on the Distance Formula

Click HERE for Help on the Density Formula

Click HERE to have a Density Calculator