Question

In 1971, the average price of gasoline was $0.36 per gallon. In 2020, the average price of gasoline was $2.32 per gallon. a. What is the percent increase, rounded to the nearest whole number, in the cost of a gallon of gasoline from 1971 to 2020? b. What is the percent decrease, rounded to the nearest whole number, in the cost of a gallon of gasoline from 2020 to 1971? 2. Last year, DeKalb Middle School had 140 7 thgraders. The number of 8 thgraders was 125% of the number of 7 thgraders. How many 8 thgraders were there last year? 3. Find the balance of a savings account at the end of 4 years if the interest earned each year is 5.5%. The principal is $700.

Answer 1

1. a. 544%

b. 84%

2. 175

3. $867.18

Explanation:

1. a.2.32-0.36=1.96

1.96/0.36=5.44

5.44*100=544

b. 1.96/2.32=0.84

0.84*100=84

2. let x = # of 7th graders

let y = # of 8th graders

y is 125% of x

y=1.25x

x=140

y=1.25*140

y=175

3. A=P(1+r)^t

A=700(1+0.055)^4

A=867.18