A math test has two parts. Both parts have the same number of questions. Rachael answered 2/3 of the questions correctly in the first part of the test, but she only answered 1/2 of the questions correctly in the second part of the test. Overall, she answered 21 questions correctly. What is the total number of questions on the test?

Step-by-step explanation:

21=1/2 so if thats 21 the answer would be 2/3=34

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!