Refer to Example 13. (i) Complete the following table:
(ii) A student argues that ‘there are 11 possible outcomes 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12. Therefore, each of them has a probability
Do you agree with this argument? Justify your answer.
(i) Total no. Of outcomes = 36
• (1, 2) and (2, 1) are events for getting a sum as 3
P (E) = 2/36 = 1/18
• (1, 3), (2, 2) and (3, 1) are the events of getting the Sum 4
P(E) = 3/36 = 1/12
• (1, 4), (2, 3), (3, 2) and (4, 1) are the events of getting the sum 5
P(E) = 4/36 = 1/9
• (1, 5), (2, 4), (3, 3), (4, 2) and (5, 1) are the events of Getting a sum 6
P(E) = 5/36
• (1, 6), (2, 5), (3, 4), (4, 3), (5, 2) and (6, 1) are the event of getting a sum 7
P(E) = 6/36 = 1/6
• (3, 6), (4, 5), (5, 4) and (6, 3) are the events of getting a sum 9
P(E) = 4/36 = 1/9
• (4, 6), (5, 5) and (6, 4) are the events of getting a sum 10
P(E) = 3/36 = 1/12
• (5, 6), (6, 5) are the events of getting a sum 11
P(E) = 2/36 =1/18
(ii) No, the eleven sum is not equally likely.
Find the zeroes of the following quadratic polynomials and verify the relationship between the zeroes and the coefficients.
(i) x2 – 2x – 8 (ii) 4s2 – 4s + 1 (iii) 6x2 – 3 – 7x (iv) 4u2 + 8u (v) t2 – 15 (vi) 3x2 – x – 4
A cottage industry produces a certain number of pottery articles in a day. It was observed on a particular day that the cost of production of each article (in rupees) was 3 more than twice the number of articles produced on that day. If the total cost of production on that day was Rs 90, find the number of articles produced and the cost of each article.
Find two consecutive positive integers, sum of whose squares is 365.
Find a quadratic polynomial each with the given numbers as the sum and product of its zeroes respectively.
The graphs of y = p(x) are given in Fig. 2.10 below, for some polynomials p(x). Find the number of zeroes of p(x), in each case.
Is the following situation possible? If so, determine their present ages.
The sum of the ages of two friends is 20 years. Four years ago, the product of their ages in years was 48.
Find two numbers whose sum is 27 and product is 182.
Prove that 3 + 2√5 is irrational.
Find the nature of the roots of the following quadratic equations. If the real roots exist, find them:
(i) 2x2 – 3x + 5 = 0 (iii) 2x2– 6x + 3 = 0
Check whether the first polynomial is a factor of the second polynomial by dividing the second polynomial by the first polynomial:
(i) t2 – 3, 2t4 + 3t3 – 2t2 – 9t – 12
(ii) x2 + 3x + 1, 3x4 + 5x3 – 7x2 + 2x + 2
(iii) x3 – 3x + 1, x5 – 4x3 + x2 + 3x + 1
The angle of elevation of the top of a building from the foot of the tower is 30° and the angle of elevation of the top of the tower from the foot of the building is 60°. If the tower is 50 m high, find the height of the building.
Find two numbers whose sum is 27 and product is 182.
Find the LCM and HCF of the following pairs of integers and verify that LCM × HCF = product of the two numbers.
(i) 26 and 91 (ii) 510 and 92 (iii) 336 and 54
A statue, 1.6 m tall, stands on the top of a pedestal. From a point on the ground, the angle of elevation of the top of the statue is 60° and from the same point the angle of elevation of the top of the pedestal is 45°. Find the height of the pedestal.
The graphs of y = p(x) are given in Fig. 2.10 below, for some polynomials p(x). Find the number of zeroes of p(x), in each case.
Find the roots of the following quadratic equations by factorisation:
Draw a circle and two lines parallel to a given line such that one is a tangent and the other, a secant to the circle.
Find two consecutive positive integers, sum of whose squares is 365.
A cottage industry produces a certain number of pottery articles in a day. It was observed on a particular day that the cost of production of each article (in rupees) was 3 more than twice the number of articles produced on that day. If the total cost of production on that day was Rs 90, find the number of articles produced and the cost of each article.
The altitude of a right triangle is 7 cm less than its base. If the hypotenuse is 13 cm, find the other two sides.