Percentage Increase and Decrease Problems

This video tutorial covers the concepts of increasing and decreasing values in math, focusing on percent changes. It includes drawing diagrams to represent these changes, expressing percent changes as a percentage of the initial amount, and graphing relationships between diameter and circumference of circles. Additionally, it explains equations for flour purchase relationships and provides instructions on finding illustrative math lessons.

In a diagram where x is divided into four equal sections and y is three out of four of those sections, what is the percentage decrease of y relative to x?

• 50% decrease

• 25% decrease

• 75% increase

• 25% increase

If x is divided into four equal sections and y is five equal sections, what is the percentage increase of y relative to x?

• 20% increase

• 10% increase

• 30% increase

• 25% increase

A bakery used 40% more flour this month compared to last month. If last month's usage is represented by 20 sections, how many sections represent this month's usage?

• 24 sections

• 28 sections

• 30 sections

• 32 sections

The bakery used 75% less milk this month compared to last month. What percentage of last month's milk usage does this month's usage represent?

• 20%

• 25%

• 15%

• 10%

If there was 40% more snow this year than last year, what percentage of last year's snow does this year's snow represent?

• 120%

• 130%

• 140%

• 150%

This year, there were 25% fewer sunny days than last year. What percentage of last year's sunny days does this year's sunny days represent?

• 65%

• 70%

• 75%

• 80%

If a runner's marathon time was 10% less than the previous marathon, what percentage of the previous marathon's time is the current marathon's time?

• 95%

• 80%

• 85%

• 90%

What is the relationship between the diameter and circumference of a circle?

• The circumference is half the diameter

• The circumference is equal to the diameter

• The circumference is twice the diameter

• The circumference is pi times the diameter

Claire bought 3/8 more flour than Priya. If Priya bought x grams, which equation represents the amount of flour Claire bought?

• y = x + 1/2x

• y = x + 3/8x

• y = x + 3/8

• y = x + 1/4x

If Priya bought x grams of flour and Claire bought 3/8 more, what is the equivalent expression for the amount Claire bought?

• 11/8x

• 9/8x

• 10/8x

• 12/8x