Question

test prep

1. in a jar, 25% of the marbles are red. if there are 45 red marbles in the jar, how many marbles are in the jar altogether?

a 60 \tc 180
b 70 \td 1,125

1. on a 747 airplane, 20% of the seats are business class. if 80 passengers can ride in business class, how many passengers can the plane carry?

a 100 \tc 320
b 160 \td 400

1. about 10% of people are left - handed. if there are 480 people in a movie theater, about how many of them are likely to be left - handed?
2. mr. ramos pays 22% of his income for housing. if mr. ramos pays $8,800 for housing, how much money did he earn during the year?

Explanation:

Question 13

Step1: Define the variable

Let \( x \) be the total number of marbles in the jar.

Step2: Set up the equation

We know that 25% of \( x \) is 45. Mathematically, this is \( 0.25x = 45 \).

Step3: Solve for \( x \)

To find \( x \), we divide both sides of the equation by 0.25: \( x=\frac{45}{0.25} = 180 \).

Step1: Define the variable

Let \( x \) be the total number of passengers the plane can carry.

Step2: Set up the equation

20% of \( x \) is 80, so \( 0.20x = 80 \).

Step3: Solve for \( x \)

Divide both sides by 0.20: \( x = \frac{80}{0.20}=400 \).

Step1: Identify the percentage and total

We have 10% of 480 people are left - handed.

Step2: Calculate the number

To find 10% of 480, we convert 10% to a decimal (0.10) and multiply by 480: \( 0.10\times480 = 48 \).

Answer:

C. 180

Question 14