Step-by-step explanation: Given that Kristie has taken five tests in science class. The average of all five of Kristie's test scores is 94 and the average of her last three test scores is 92.

We are to find the average score of her first two tests.

Let a1, a2, a3, a4 and a5 be teh scores of Kristle in first , second, third, fourth and fifth tests respectively.

Then, according to the given information, we have

$\dfrac{a1+a2+a3+a4+a5}{5}=94\\\\\Rightarrow a1+a2+a3+a4+a5=94\times5\\\\\Rightarrow a1+a2+a3+a4+a5=470~~~~~~~~~~~~~~~~~~~~~~~~~~~(i)$

and

$\dfrac{a3+a4+a5}{3}=92\\\\\Rightarrow a3+a4+a5=92\times3\\\\\Rightarrow a3+a4+a5=276~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~(ii)$

Subtracting equation (ii) from equation (i), we get

$(a1+a2+a3+a4+a5)-(a3+a4+a5)=470-276\\\\\Rightarrow a1+a2=194\\\\\Rightarrow \dfrac{a1+a2}{2}=\dfrac{194}{2}\\\\\Rightarrow \dfrac{a1+a2}{2}=97.$

Thus, the average of the first two test scores is 97.

6 0

3 years ago

Please answer answer question

Sophie [7]

Answer:

The correct answer is

Step-by-step explanation:

11 square centimeters.

Hope this helps....

Have a nice day!!!!

8 0

4 years ago

Read 2 more answers

Please help with this question it is 60% of my grade.

Vsevolod [243]

Answer: b

Step-by-step explanation:

you start with 0 min- equals 24

1 min- 21

2 min- 18

3 min- 15

4 min- 12

5 min- 9

and so on- you look for the table that best describes that. x represents the minutes, and y represent the amount of water left in the sink.

3 0

3 years ago

Read 2 more answers