25 points! Please help!

17.5(D)

Step-by-step explanation:

So, lets see:

Every 5 minutes, Raul answers 22 questions.

The test has 77 questions.

We must figure out the time it takes to answer all 77 questions.

To do this, lets first divide the total questions by the questions answered per 5 minutes:

77 / 22

=

3.5

I got 3.5 knowing that 3x22 is 66, and half(0.5) of 22 is 11, and 11 plus 66 is 77.

So, the 3.5 is how many times he answrs 22 questions in five minutes.

To make a bit more sense, basically we have to multiply the 5 minutes by the 3.5:

3.5*5

=

17.5

We know that 3 times 5 is 15. Half(0.5) of 5 is 2.5, so 15+2.5 is 17.5.

So the answer is that for the 77 quesitons, it takes 17.5 minutes

HOPe this helps!

option (b) is correct

step-by-step explanation:

to find the solution of this system, we need to convert it into reduced row-echelon form. we have,

after applying row operations r2 -> r2/2 and r3 -> r3/3, we get,