Let a pencil cost ₹x and a pen ₹y. Equations are 5x + 7y = 50 and 7x + 5y = 46. Adding gives x + y = 8. Subtracting gives x − y = −2. Solving yields x = ...
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Let a citron cost x and a wood-apple y. Adding 9x + 7y = 107 and 7x + 9y = 101 gives x + y = 13. Subtracting gives x − y = 3. Adding both yields x = 8 ...
Box volume is 16 × 8 × 8 = 1024 cm³. The volume of 16 spheres is 16 × (4/3)π(2)³ ≈ 536.17 cm³. Liquid volume is 1024 − 536.17 = 487.83 cm³, which rounds to 488 cm³. Class 9 Ganita Manjari ...
For radius 21 cm: (i) Curved surface area is 2πr² = 2 × (22/7) × 21² = 2772 cm². (ii) Total surface area is 3πr² = 3 × (22/7) × 21² = 4158 cm². Class 9 Ganita Manjari part 2 Chapter ...
The ratio of their diameters and radii is 1 : 4. Since the surface area of a sphere is proportional to the square of its radius, the ratio of their surface areas is 1² : 4² = 1 : 16. Cbse ...