Question 11 - Figure it out - Page 19, 20 - Chapter 1 Class 8 - Fractions in Disguise (Ganita Prakash II)

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Question 11 The population of elephants in a national park increased by 5% in the last decade. If the population of the elephants last decade is p, the population now is (i) p × 0.5 (ii) p × 0.05 (iii) p × 1.5 (iv) p × 1.05 (v) p + 1.50 Given Percentage increase = 5% Original population = p Now, Percentage increase = (𝐶ℎ𝑎𝑛𝑔𝑒 𝑖𝑛 𝑝𝑜𝑝𝑢𝑙𝑎𝑡𝑖𝑜𝑛)/(𝑂𝑟𝑖𝑔𝑖𝑛𝑎𝑙 𝑝𝑜𝑝𝑢𝑙𝑎𝑡𝑖𝑜𝑛) × 100 Percentage increase = (𝑷𝒐𝒑𝒖𝒍𝒂𝒕𝒊𝒐𝒏 𝒏𝒐𝒘 − 𝑶𝒓𝒊𝒈𝒊𝒏𝒂𝒍 𝒑𝒐𝒑𝒖𝒍𝒂𝒕𝒊𝒐𝒏)/(𝑶𝒓𝒊𝒈𝒊𝒏𝒂𝒍 𝒑𝒐𝒑𝒖𝒍𝒂𝒕𝒊𝒐𝒏) × 100 Putting values 5 = (𝑷𝒐𝒑𝒖𝒍𝒂𝒕𝒊𝒐𝒏 𝒏𝒐𝒘 −𝒑)/𝒑 × 100 5/100 = (𝑃𝑜𝑝𝑢𝑙𝑎𝑡𝑖𝑜𝑛 𝑛𝑜𝑤 −𝑝)/𝑝 0.05 = (𝑃𝑜𝑝𝑢𝑙𝑎𝑡𝑖𝑜𝑛 𝑛𝑜𝑤 −𝑝)/𝑝 0.05 × p = Population now – p 0.05 × p + p = Population now Population now = 0.05 × p + p Population now = p × (0.05 + 1) Population now = p × 1.05 Thus, correct option is (iv) - p × 1.05