Proportions and Ratios in Context

The video tutorial begins with a warm-up ratio problem, demonstrating how to solve it using cross multiplication. It then progresses to more complex word problems, including calculating the heights of mountains using given ratios and determining the proportion of students with cell phones older than one year. The tutorial emphasizes understanding the logic behind cross multiplication and applying it to real-world scenarios.

What is the result of cross-multiplying the ratio 13/6 = 5/x?

• 13x = 5

• 13x = 6 * 5

• 13x = 30

• 13x = 5 * 6

What is the value of x in the equation 13/6 = 5/x after solving?

• x = 5/6

• x = 6/5

• x = 13/30

• x = 30/13

If Mount Elbert is 220/67 the height of Ben Nevis, what is the height of Ben Nevis if Mount Elbert is 4,400 meters?

• 1,340 meters

• 1,200 meters

• 2,000 meters

• 1,500 meters

What is the height of Mount Yukon if it is 298/67 the size of Ben Nevis, and Ben Nevis is 1,340 meters?

• 5,800 meters

• 5,960 meters

• 6,000 meters

• 6,100 meters

In a school, if 2 out of 3 students have a cell phone, what fraction of students have a cell phone?

• 1/2

• 3/5

• 2/3

• 1/3

If 1 in 5 students have a cell phone that is one year old or less, what fraction of students have such phones?

• 1/6

• 1/5

• 1/4

• 1/3

What is the proportion of students who have a cell phone that is more than one year old?

• 6/15

• 7/15

• 8/15

• 9/15

Out of the students who own a cell phone, what proportion owns a phone that is more than one year old?

• 1/2

• 3/5

• 7/10

• 2/5

If 2/3 of students have a cell phone, and 1/5 of all students have a new phone, what fraction of students have an older phone?

• 5/15

• 7/15

• 8/15

• 6/15

What is the final step to find the proportion of students with older phones?

• Add 1/5

• Subtract 1/5

• Divide by 3/2

• Multiply by 2/3