Question 2. (ALL CALCULATIONS MUST BE DONE WITHOUT USING A CALCULATOR) 2.1.1 Increase R68 in the ratio \( 7: 4 \) 2.1.2 Decrease \( 91 x \) in the ratio \( 5: 7 \). 2.1.3 Divide 182 kg in the ratio \( 2: 3: 8 \). 2.2 A farmer can exchange 72 pigs for 54 sheep at R560 each. What is the price of a pig 2.3 The ratio of the number of boys to the number of girls in a class is \( 4: 3 \). 2.3.1 Calculate how many boys there are in the class if there are 42 pupils in the class. 2.3.2 Calculate how many pupils there are in the class if there are 21 girls. Question 3
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To increase R68 in the ratio of 7:4, first recognize that the combined parts of the ratio equal 7 + 4 = 11. To find the increase, divide R68 by 11 to get R6.18 (approximately). Multiply that by 7 for the increased portion: 7 x R6.18 = R43.18 (approximately). Add this amount to R68 for the final total: R68 + R43.18 = R111.18 (approximately). To decrease \( 91x \) in the ratio of 5:7, again, the total parts are 5 + 7 = 12. Divide \( 91x \) by 12, which gives you \( 7.58x \) (approximately) for each part. For the decreased portion (5 parts), calculate \( 5 \times 7.58x \), which is approximately \( 37.9x \). Finally, subtract that from \( 91x \) to find your new value: \( 91x - 37.9x = 53.1x \) (approximately). In this scenario, if a farmer exchanges 72 pigs for 54 sheep at R560 each, that means the total value of the sheep is \( 54 \times R560 = R30,240 \). To find the price of a pig, you need to determine the value of the pigs exchanged; thus \( R30,240 / 72 = R420 \) is the price per pig. It’s a straightforward calculation where you divide total value by total quantity. With a ratio of boys to girls as 4:3 and a total of 42 pupils in the class, you can find the number of boys by calculating the parts, which means there are \( 4x + 3x = 42 \) pupils in total. Solving for x gives \( 7x = 42 \) or \( x = 6 \). Therefore, the number of boys is \( 4x = 4 \times 6 = 24 \) boys. For the scenario with 21 girls, you can use the same ratio of boys to girls (4:3). If the girls are represented as 3 parts and there are 21 girls, you can find x by dividing 21 by 3 (which means \( x = 7 \)). Therefore, the total number of pupils in the class, which includes boys as well, is \( 7x + 21 = 7 \times 4 + 21 = 28 + 21 = 49 \) pupils.