When we take an average of something, we have to add up all the data on the somethings and then divide by the number of somethings we have. Ed takes 5 tests, and we have scores for them; we also have his current average. What we don't know for sure are 2 of the 5 test scores, but we have enough to determine what they are.

If one test has a score of x, and the other test is 3 points less than that, the score on that last test is x - 3. Putting all of that together into an average problem:

$\frac{87+85+87+x+(x-3)}{5}=90$ and simplfiying a bit:

$\frac{256+2x}{5}=90$ . Multiply both sides by 5 to get

256 + 2x = 450; subtract 256 from both sides to get

2x = 194 and divide by 2:

x = 97

The one test score was a 97 and the other one, which was 3 less than that, was a 94.

3 0

3 years ago

How do I find the mass of 250.0mL

kupik [55]

Answer:

mass = density · volume

Step-by-step explanation:

To find the mass of a given volume, multiply your given volume by the <em>density</em>. Often, density is given in grams per cubic centimeter. 1 cubic centimeter is the same as 1 milliliter.

4 0

3 years ago

: 2/18 of the students in Mr. P’s classroom had blonde hair. If there were 36 students in his class, how many students did not h

sesenic [268]

4 did not have blonde hair

7 0

2 years ago