Q) The graph of the polynomial – ax²+bx+c is shown below. Write the signs of ‘a’ and ‘b² – 4ac’. Ans: Clearly, f(x) = ax² + bx + c represent a parabola opening upwards. Therefore, a>0 Since, the parabola cuts the x-axis at two points, this means that the polynomial will have two real solutions. Hence, […]
December 2023
Q) ABCD is a rectangle if the value of AB= 12 is given, find the values of x and y. Ans: We know, opposite sides of a rectangle are equal, ∴ x + y = 12 —-(1) and, x – y = 8 —-(2) By elimination method, we subtract (2) from (1), Therefore, 2y =
ABCD is a rectangle if the value of AB=12 is given. Find the values of x and y. Read More »
Q) From a group of 3 boys and 2 girls we select two children. What is the set representing the event:i. one girl is selectedii. at least one girl is selected Ans: Let’s first find out all possible sets of selecting two children:Let 3 boys are B1, B2, B3 and 2 girls are G1, G2, then the
From a group of 3 boys and 2 girls we select two children. What is the set Read More »
Q) The following table gives the heights (in cm) of a group of 55 students in a class. Compute the modal height and interpret the result. Ans: Since the modal class is the class with the highest frequency. In the given question, class “146 – 148” has 12 students (i.e. highest frequency of 12). Hence,
The following table gives the heights (in cm) of a group of 55 students in a class. Read More »
Q) For the following distribution, calculate mean using all suitable methods: Ans: 1. Direct Method To calculate Mean value of the distribution, Let’s re-arrange the data with midpoint of each class, frequency, and multiply midpoint with frequency: We know that, mean of grouped data is given by: Mean of grouped data = Therefore, Mean = = 13.25
For the following distribution, calculate mean using all suitable methods: Read More »
Q) Find the value of m for which the quadratic equation (m + 1) y2 – 6(m+1) y + 3(m+9) = 0, m ≠ -1 has equal roots. Hence find the roots of the equation. [CBSE, Sample Question Paper – Standard – 2024] Ans: Given quadratic equation is: (m
Find the value of m for which the quadratic equation (m + 1) y2 – 6(m+1) y + 3(m+9)= 0 Read More »
Q) If a line is drawn parallel to one side of a triangle to intersect the other two sides in distinct points, then prove that the other two sides are divided in the same ratio. Ans: Given: Let D and E be two distinct points on AB and AC respectively such that DE ǁ BC.