Question

1. a collector bought a rare coin for $30. the coin is now valued at $37.50. select all the true statements.

(a) the scenario represents a percent increase.
(b) the scenario represents a percent decrease.
(c) the percent of change was 20%.
(d) the percent of change was 25%.
(e) the percent of change was 75%.

1. a coffee - machine dispenses 8 - ounce cups of coffee automatically. the amount of coffee may vary by 3%. what are the least and greatest number of ounces the coffee machine may dispense?

least number: ounces greatest number: ounces

1. a german shepherd puppy weighed 25 pounds at 4 months old and 31 pounds at 5 months old. what is the percent increase or decrease of its weight?

(a) 24% increase
(b) 35% decrease
(c) 35% increase
(d) 54% decrease

1. the butterfly population at glen arbor farms was 250 last year. this year there are 100 butterflies. what is the percent increase or decrease?

(a) 50% decrease
(b) 50% increase
(c) 60% decrease
(d) 60% increase
spiral review

1. there is a proportional relationship between time in hours and time in days.

a. what is the constant of proportionality?
b. what equation describes this relationship?

1. a triangle has a base length of 10 inches and a height of 4 inches. what is the area of the triangle?

Explanation:

10.

Step1: Determine percent - change type

Since the value of the coin increased from $30 to $37.50, it's a percent increase.

Step2: Calculate percent change

The formula for percent change is $\frac{\text{new value}-\text{old value}}{\text{old value}}\times100\%$. Here, the old value is $30 and the new value is $37.50. So, $\frac{37.50 - 30}{30}\times100\%=\frac{7.5}{30}\times100\% = 25\%$.

Step1: Calculate least amount

The least amount is $8\times(1 - 0.03)=8\times0.97 = 7.76$ ounces.

Step2: Calculate greatest amount

The greatest amount is $8\times(1 + 0.03)=8\times1.03=8.24$ ounces.

Step1: Calculate amount of change

The amount of change is $31 - 25=6$ pounds.

Step2: Calculate percent change

The percent change is $\frac{31 - 25}{25}\times100\%=\frac{6}{25}\times100\% = 24\%$. Since the weight increased, it's a 24% increase.

Answer:

A. The scenario represents a percent increase.
D. The percent of change was 25%.

11.