72 is the minimum grade he must get on the last test in order to have an average of 77.
<u>Step-by-step explanation:</u>
The grades of a student are given 72,91,78,72 and the grade of his last test is not given.
- You have to find the minimum grade the student shall get, so that the student average must be 77.
- The four grades are already given. Therefore, we need to find only the fifth grade.
The term average is defined as the sum of all the data in a set divided by the number of data in a set.
Here, the number of data is 5. (Because the students has 4 grades plus one grade for his last test).
The average he should get is 77.
Average = Sum of all grades / number of grades
Let, 'x' be the grade of the last test.
⇒ 77 = (72+91+78+72+x) / 5
⇒ 77 = (313+x) / 5
⇒ 385 = 313 + x
⇒ x = 385 - 313
⇒ x = 72
The minimum grade he must get on the last test is 72.
2100/1 or 4200/2, could be either
Answer:
10.1%
Step-by-step explanation:
The first thing we should do is calculate the total volume of the solution when mixing them would be:
0.7 + 0.3 = 1
Now, we have that the resulting concentration (x) would be equal to the sum of the multiplications between the volumes and the concentrations to be mixed, as follows:
x * 1 = 0.7 * 0.05 + 0.3 * 0.22
x = 0.035 + 0.066
x = 0.101
That is, the concentration of the resulting mixture would be 10.1% (0.101 * 100)
Answer: The solution is k = -171.92.
