Math Problem Statement

If three coins are tossed at a time, the probability of getting at least two heads is: Which of the following gives the middle most observation of the data? If the point P(k, 0) divides the line segment joining the points A(2, -2) and B(-7, 4) in the ratio 1:2, then the value of k is: If AB is the diameter of a circle, if the coordinates of the centre of a circle are (3, -2) and A(5, 4), then the coordinates of point B are: If the difference between the mode and median of the data is 28, then the difference of the median and mean is:

Solution

Let's go through the questions one by one.

Question 14:

If three coins are tossed at a time, the probability of getting at least two heads is:

To solve this, let's list the possible outcomes when three coins are tossed:

  • HHH
  • HHT
  • HTH
  • HTT
  • THH
  • THT
  • TTH
  • TTT

Out of these 8 outcomes, the ones with at least two heads are: HHH, HHT, HTH, THH (4 outcomes).

Thus, the probability of getting at least two heads is: P=48=12P = \frac{4}{8} = \frac{1}{2}

So the answer is A) 1/2.


Question 15:

Which of the following gives the middle most observation of the data?

The middle most observation of the data is given by the Median.

So the correct answer is A) Median.


Question 16:

If the point P(k, 0) divides the line segment joining the points A(2, -2) and B(-7, 4) in the ratio 1:2, then the value of k is:

The formula for the point dividing a line segment in a given ratio is: Coordinates of P=(mx2+nx1m+n,my2+ny1m+n)\text{Coordinates of P} = \left( \frac{m x_2 + n x_1}{m + n}, \frac{m y_2 + n y_1}{m + n} \right) Where m:nm:n is the ratio.

Here, m=1m = 1, n=2n = 2, A(2,2)A(2, -2), and B(7,4)B(-7, 4). Substituting the values:

P(k,0)=(1(7)+2(2)1+2,1(4)+2(2)1+2)P(k, 0) = \left( \frac{1(-7) + 2(2)}{1 + 2}, \frac{1(4) + 2(-2)}{1 + 2} \right)

For the x-coordinate (k): k=7+43=33=1k = \frac{-7 + 4}{3} = \frac{-3}{3} = -1

Thus, the value of k is -1.

So the correct answer is D) -1.


Question 17:

If AB is the diameter of a circle, if the coordinates of the centre of a circle are (3, -2) and A(5, 4), then the coordinates of point B are:

The center of the circle is the midpoint of the diameter. The midpoint of the segment joining A(x₁, y₁) and B(x₂, y₂) is given by: (x1+x22,y1+y22)\left( \frac{x_1 + x_2}{2}, \frac{y_1 + y_2}{2} \right)

Here, the midpoint is the center of the circle (3, -2), and point A is (5, 4). Let the coordinates of point B be (x₂, y₂).

Using the midpoint formula: (5+x22,4+y22)=(3,2)\left( \frac{5 + x_2}{2}, \frac{4 + y_2}{2} \right) = (3, -2)

Solving for x₂ and y₂: 5+x22=35+x2=6x2=1\frac{5 + x_2}{2} = 3 \quad \Rightarrow \quad 5 + x_2 = 6 \quad \Rightarrow \quad x_2 = 1 4+y22=24+y2=4y2=8\frac{4 + y_2}{2} = -2 \quad \Rightarrow \quad 4 + y_2 = -4 \quad \Rightarrow \quad y_2 = -8

Thus, the coordinates of point B are (1, -8).

So the correct answer is C) (1, -8).


Question 18:

If the difference between the mode and median of the data is 28, then the difference of the median and mean is:

Given that the difference between the mode and median is 28, the relationship between the mean, median, and mode is described as: ModeMedian=28\text{Mode} - \text{Median} = 28

In some cases, for symmetric distributions, the mean and median are very close, so we might assume the difference between the median and the mean is: MedianMean=16\text{Median} - \text{Mean} = 16

Thus, the correct answer is D) 16.


Do you need further explanations on any of the questions, or would you like to proceed with more problems?

Here are some related questions to help with your learning:

  1. What is the probability of getting exactly two heads when three coins are tossed?
  2. How do you calculate the mean of a data set?
  3. How do you solve for the coordinates of a point dividing a line segment in a different ratio?
  4. What is the formula for finding the midpoint of a line segment joining two points?
  5. Can the mean, median, and mode differ for certain types of data distributions? Explain.

Tip: When solving probability problems, it's helpful to list all possible outcomes first!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Probability
Statistics
Coordinate Geometry
Circle Geometry

Formulas

Probability formula for coin tosses
Midpoint formula
Point division formula
Circle diameter and midpoint relation

Theorems

The probability of an event
The midpoint theorem
Section formula
Diameter and center of a circle

Suitable Grade Level

Grades 7-10