Jonas earns $9 per hour as a lifeguard and $11 per hour as a swim instructor. last week he worked a total of 40 hours at the pool, 10 of which were teaching swim lessons. which expression and value show the total amount of money that he earned last week? 9 × 10 + 11 × 30; $420 9 × 10 + 11 × 30; $210 9 × 30 + 11 × 10; $419 9 × 30 + 11 × 10; $380

The correct answer is D.  9 × 30 + 11 × 10; $380

Step-by-step explanation:

Let's write the correct equation to help Jonas to find out his earnings last week, this way:

Number of hours worked by Jonas last week = 40

Number of hours worked by Jonas last week as swim instructor = 10

Number of hours worked by Jonas last week as lifeguard = 30

Rate per hour as lifeguard = $ 9

Rate per hour as swim instructor = $ 11

Now, we can answer the question:

Total earnings last week = 30 * 9 + 10 * 11

Total earnings last week = 270 + 110 = $ 380

The correct answer is D.  9 × 30 + 11 × 10; $380

first option

a function is a relation in which an input is paired with exactly one output.

so, let's find the right answer.

in our first option, our inputs are january, february, and march. the outputs are 30, 28, and 25. each input has it's own output. this is correct!

our second option we know is incorrect, because ms. valverade has two outputs, dogs and cats. this is not a function.

our third option is incorrect as well. the yellow square has two ouputs, the square and the triangle.

lastly, in our fourth option, we see the number 7 two times with a different output. therefore, this is not a function.

remember: each input must be paired with only one output!