# Tag Archives: RD Sharma Class-9

Question 8. If x2 +1/x2 = 79, find the value of x +1/x Solution: Given, x2 +1/x2 = 79 Let us take the square of x… Read More
Question 1. Evaluate each of the following using identities: (i) (2x – 1/x)2(ii) (2x + y) (2x – y)(iii) (a2b – b2a)2(iv) (a – 0.1)… Read More
Question 1: Find the surface area of a sphere of radius: (i) 10.5 cm (ii) 5.6 cm (iii) 14 cm Solution: (i) Radius (r) =… Read More
Question 1. A coin is tossed 1000 times with the following sequence:  Head: 455, Tail: 545 Compute the probability of each event. Solution: According to… Read More
Question 11. Given below is the frequency distribution table regarding the concentration of sulphur dioxide in the air in parts per million of a certain… Read More
Question 1. Factorize 64a3+125b3+240a2b+300ab2 Solution: As we know that, a3+b3+3a2b+3ab2 = (a+b)3  So, the above expression can be written as: (4a)3+(5b)3+3(4a)2(5b)+3(4a)(5b)2   (4a+5b)3 (4a+5b)(4a+5b)(4a+5b) Hence,… Read More
Question 11. A joker’s cap is in the form of a right circular cone of base radius 7cm and height 24 cm. Find the area… Read More
Question 17. A cylindrical jar of radius 6 cm contains oil. Iron spheres each of radius 1.5 cm are immersed in the oil. How many… Read More
Question 1. Find the volume of a sphere whose radius is : (i) 2 cm (ii) 3.5 cm (iii) 10.5 cm. Solution:  As we know… Read More
Question 1. Find the curved surface area of a cone, if its slant height is 6 cm and the radius of its base is 21… Read More
Question 1. Find the volume of the right circular cone with: (i) Radius 6cm, height 7cm (ii) Radius 3.5cm, height 12cm (iii) Height is 21cm… Read More
Question 1: Define an irrational number. Solution: A real number that cannot be expressed in the form of fractions i.e. p/q, where p and q… Read More
Question 1: Write the following in the expanded form: (i) (a + 2b + c)2 (ii) (2a − 3b − c)2 (iii) (−3x+y+z)2 (iv) (m+2n−5p)2… Read More
Question 1: If figure, ABCD is a parallelogram, AE ⊥ DC and CF ⊥ AD. If AB = 16 cm, AE = 8 cm and… Read More
Question 1. Find the following products? i. (3x + 2y) (9x2 – 6xy + 4y2) Solution: We know that  a3 + b3 = (a +… Read More