SCIENCE AND MATH CONCEPTS

 Probability Ex 15.1 Question 1. Complete the following statements: (i) Probability of an event E + Probability of the event ‘not E’ = ……… (ii) The probability of an event that cannot happen is ……… Such an event is called ……… (iii) The probability of an event that is certain to happen is ………. Such an event is called ……… (iv) The sum of the probabilities of all the elementary events of an experiment is ……….. (v) The probability of an event is greater than or equal to …………. and less than or equal to ……….. Solution: Question 2. Which of the following experiments have equally likely outcomes? Explain. (i) A driver attempts to start a car. The car starts or does not start. (ii) A player attempts to shoot a basketball. She/he shoots or misses the shot. (iii) A trial is made to answer a true-false question. The answer is right or wrong. (iv) A baby is born. It is a boy or a girl. Solution: Question 3. Why is tossing a coin considered to be a fair way of deciding which team should get th

Coordinate Geometry Ex 7.1 Question 1. Find the distance between the following pairs of points: (i) (2, 3), (4, 1) (ii) (-5, 7), (-1, 3) (iii) (a, b), (-a, -b) Solution: Question 2. Find the distance between the points (0, 0) and (36, 15). Solution: Question 3. Determine if the points (1, 5), (2, 3) and (-2, -11) are collinear. Solution: Question 4. Check whether (5, -2), (6, 4) and (7, -2) are the vertices of an isosceles triangle. Solution: Question 5. In a classroom, 4 friends are seated at the points A, B, C and D as shown in the given figure. Champa and Chameli walk into the class and after observing for a few minutes Champa asks Chameli, “Don’t you think ABCD is a square?” Chameli disagrees. Using distance formula, find which of them is correct. Solution: Question 6. Name the type of quadrilateral formed, if any, by the following points, and give reasons for your answer. (i) (-1, -2), (1, 0), (-1, 2), (-3, 0) (ii) (-3, 5), (3, 1), (0, 3), (-1, -4) (iii) (4, 5), (