Answer:
D. The correct value of c = 7.4
Step-by-step explanation:
According to Tangent-Secant theorem:
"When a tangent and a secant are drawn from one single external point to a circle, square of the length of tangent segment must be equal to the product of lengths of whole secant segment and the exterior portion of secant segment."
Here, the external length of tangent segment = 10
Also, the length of internal segment is 14 and c.
So, by the SECANT THEOREM:

or, c = 7. 1428
Now, rounding off the value of c = 7. 14 to the nearest tenth, we get
c = 7. 4
Hence the correct value of c = 7.4
Answer: 5 minutes
Step-by-step explanation:
Answer:
He answered 20 questions correctly.
Step-by-step explanation:
25×.8(80%) = 20.
Given that the score of the student on the quiz was 25c - 10(15 - c)
It can be seen that the first term of expression for her score (i.e. 25c) shows that 25 marks were awarded to each correct answer.
The second term of the expression (i.e. 10(15 - c)) represent that 10 marks were deducted from each wrong answer.
Thus, the number of wrong answers is 15 - c.
The sum of the correct answers and the wrong answers gives the total number of questions in the quiz.
Thus, the total number of questions in the quiz is given by 15 - c + c = 15.
Therefore, there are 15 questions in the quiz.