FIND DEPENDENT AND INDEPENDENT VARIABLE

Problem 1 :

As a babysitter, you earn $5 for every hour you babysit.

Which is the dependent variable?

A) Number of hours you babysit

B) Number of children you babysit

C) Amount of money you earn per hour

D) Total amount of money you earn

Solution :

Let x be the number of hours you baby sit. Let y be the amount he earns.

y = 5x

Dependent variable = Total amount of money you earn

Problem 2 :

Which is the independent variable in the following equation?

y = 3x + 9

A) y     B)  x       C) 3       D) 9

Solution :

Independent variable = x

Here,

y = 3x + 9

if x = 1, y = 12

if x = 2, y = 15

So, x is the independent variable.

Problem 3 :

Mary can make 5 hair bows every hour.

Which is the independent variable?

A) Total number of hair bows Mary made

B) Number of hair bows made per hour

C) Number of hours Mary made bows

D) Price of each hair bow

Solution :

Independent variable = Number of hours Mary made bows

Here,

Total number of hair bows Mary can make depends on the number of hours.

Also, price of each bow depends on number of bows she’s making.

Problem 4 :

Juan earns flat fee of $150 plus $20 for every hour he works decorating a house. Which graph correctly displays Juan’s earnings?

Solution :

If he work one hour,

= 150 + 20 × 1

= 170

If he work two hour,

= 150 + 20 × 2

= 190

So, option (D) is correct.

Problem 5 :

The table shows the number of hours it takes to mow a certain number of lawns.

which graph represents the relationship shown in the table ?

Solution :

For one hour, 2 lawns moved and for 2 hours, 4 lawns moved.

So, option (B) is correct.