Rate of Change and Proportions

The video tutorial covers the concepts of ratios and proportions, starting with an introduction and example of calculating unit rates. It then moves on to practical examples, including calculating the rate of snowfall and analyzing changes in grades over time. The tutorial also demonstrates solving proportions using cross multiplication and concludes with a problem involving calculating funds raised from selling boxes.

What is the unit rate of envelopes stamped per minute if Cody stamped 460 envelopes in 30 minutes?

• 16 envelopes/minute

• 15 envelopes/minute

• 14.5 envelopes/minute

• 15.33 envelopes/minute

If Max measured 2 inches of snow at 7 a.m. and 5 inches at 10 a.m., what is the rate of snowfall per hour?

• 1 inch/hour

• 1.5 inches/hour

• 2 inches/hour

• 0.5 inches/hour

How much did Chrissy's grade increase per week from the first to the second quarter?

• 4 points/week

• 1 point/week

• 2 points/week

• 3 points/week

What was the rate of change in Chrissy's grade from the second to the third quarter?

• Increased by 2 points/week

• Decreased by 1 point/week

• Decreased by 2 points/week

• Increased by 1 point/week

In solving a proportion, if 12x = 156, what is the value of x?

• 14

• 15

• 13

• 12

If $26 is raised by selling 8 boxes of cookies, how much will be raised by selling 40 boxes?

• $140

• $130

• $120

• $100