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Grade 12 Placement test Choose the correct Answer 1. Find all zeros of the trinomial \( k(x)=x^{2}+10 x-200 \). A. \( (-10,0),(20,0) \) B. \( (-5,-255),(0,-225) \) e. \( (0,10),(0,-20) \) D. \( (10,0),(-20,0) \) 2. Simplify \( \left(\frac{2}{3}+4 i\right)(3-i) \).

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Ankur S

Numerade educator

From the units of measuring density ......... (a) N . m?³ (b) g.mm?¹ (c) kg . cm?² (d) g . cm?³

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Ankur S

Numerade educator

If the relative density of ice is 0. 91, what will be the decrease in volume when 50 g of ice melt? (a) 3.2 cm³ (b) 4.9 cm³ (c) 5.6 cm³ (d) 7.4 cm³

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Ankur S

Numerade educator

Two quantities of two liquids ( X ), ( Y ) that don't react with each other are mixed together, their volumes are ( V_{o l}, 2 mathrm{~V}_{o l} ) respectively, if the density of liquid ( X ) is ( 1000 mathrm{~kg} / mathrm{m}^{3} ) and the density of liquid ( Y ) is ( 2000 mathrm{~kg} / mathrm{m}^{3} ), assuming that the total volume of the liquids doesn't change after mixing, then the density of the mixture equals (a) ( 3000 mathrm{~kg} / mathrm{m}^{3} ) (b) ( 1666.7 mathrm{~kg} / mathrm{m}^{3} ) (c) ( 1500 mathrm{~kg} / mathrm{m}^{3} ) (d) ( 133.3 mathrm{~kg} / mathrm{m}^{3} )

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Supratim Pal

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The opposite table lists the mass percentages of gold and copper in some known gold alloys, given that the densities of gold and copper are 19300 kg/m³, 8900 kg/m³ respectively, which of these alloys has the least density? | Alloy | Gold percentage | Copper percentage | | :---: | :---: | :---: | | A | 91.7% | 8.3% | | B | 87.5% | 12.5% | | C | 75% | 25% | | D | 58.3% | 41.7% | (a) Alloy A (b) Alloy B (c) Alloy C (d) Alloy D

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Ankur S

Numerade educator

A graduated cylinder contains ( 40 mathrm{~cm}^{3} ) of glycerin whose density is ( 1.26 mathrm{~g} / mathrm{cm}^{3} ), then an amount of water of density ( 1 mathrm{~g} ) ( / mathrm{cm}^{3} ) is added to the glycerin, so that the density of the mixture becomes ( 1.1 mathrm{~g} / mathrm{cm}^{3} ). If the total volume of the liquids doesn't change after mixing them, the volume of the added water equals is (a) ( 40 mathrm{~cm}^{3} ) (b) ( 44 mathrm{~cm}^{3} ) (c) ( 52 mathrm{~cm}^{3} ) (d) ( 64 mathrm{~cm}^{3} )

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Prabhat Tyagi

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A metallic alloy has a mass of ( 750 mathrm{~g} ) where ( 60 % ) of its mass is magnesium while the other part is copper. If the density of magnesium is ( 1.7 mathrm{~g} . mathrm{cm}^{-3} ) and the density of copper is ( 9 mathrm{~g} . mathrm{cm}^{-3} ), so the relative density of the material of the alloy equals (Where: ( ho_{ ext {water }}=1 mathrm{~g} / mathrm{cm}^{3} ) ) (a) 2.5 (b) 4.6 (c) 5.4 (d) 10.7

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Ankur S

Numerade educator

The opposite figure shows two glass beakers containing different amounts of water that has density of 1000 kg/m³. If these two amounts of water get added to each other while keeping the temperature constant, the final density of the mixture of liquid becomes (a) 500 kg/m³ (b) 800 kg/m³ (c) 1000 kg/m³ (d) 2000 kg/m³

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Prabhat Tyagi

Numerade educator

How many grams of iron are required to make an iron hollow sphere of inner radius 15 cm and outer radius 25 cm as in the opposite diagram? (Given that: The density of iron = 7.8 g/cm3 ) (a) 293.3 g (b) 400.4 × 103 g (c) 513.9 × 103 g (d) 2.1 × 103 g

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Ankur S

Numerade educator

A displacement can is filled with water. When a piece of copper of mass 531.25 g is immersed in the can, it has displaced 62.5 g of water. Then the density of copper is (Where: ?water = 1000 kg/m³) (a)5312.5 kg/m³ (b)6250 kg/m³ (c) 7500 kg/m³ (d)8500 kg/m³

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Malak a.