# Ratio and Proportion- Aptitude Questions and Answers

 175 men can dig a canal of 3150 meters long in 36 days. How many men are required to dig a canal of 3900 meters long in 24 days? A) 325 B) 350 C) 375 D) 400 Correct Answer : 325 Explanation :175 men*36 days / X men*24 days = 3150 meters/3900 meters 175 *36 *3900 = 3150 *24 *X X = 175 *36 *3900 / 3150 *24 X = 325 So, 325 men are required. A bag contains red, blue and black balls. The ratio of red to blue balls is 3 : 5. The ratio of black to red balls is 3 : 4. What is the ratio of blue to black balls? A) 5 : 3 B) 4 : 5 C) 9 : 20 D) 20 : 9 Correct Answer : 20 : 9 Explanation :ratio of red to blue balls= red / blue = 3 / 5 ratio of black to red balls= black / red = 3 / 4 ratio of black to blue balls= (black / red) * (red / blue) = (3 / 4) * (3 / 5) = 3*3 / 4*5 = 9 / 20 Hence, ratio of blue to black balls = 1 /(9/20) = 20/9 2/7 of the stamps in Ravi's stamp collection are Indian stamps and the remaining are foreign stamps. What is the ratio of Indian stamps to foreign stamps in Ravi's stamp collection? A) 2 : 5 B) 5 : 7 C) 5 : 2 D) 7 : 5 Correct Answer : 2 : 5 Explanation :Total 7 stamps 2 are Indian stamps Indian + Foreign stamps = 7 2 + Foreign stamps = 7 Foreign stamps = 5 the ratio of Indian stamps to Foreign stamps in Ravi’s collection= 2/5 A certain sum was divided among A, B and C in the ratio 5 : 7 : 6. If B received Rs 4500 more than C, find C's share? A) 30,000 B) 27,000 C) 25,000 D) 23,000 Correct Answer : 27,000 Explanation :Let the amount received by A, B, c be 5x, 7x and 6x respectively. Since B received 4500 more than C, 7x-6x = 4500 x = 4500 C's share = 6x = 6*4500 = 27000 Hence, C's share is Rs 27000 Rs 750 are divided among A, B and C in such a manner that A : B = 5 : 2 and B : C = 7 : 13, What is A’s share? A) Rs 250 B) Rs 300 C) Rs 350 D) Rs 400 Correct Answer : Rs 350 Explanation :Given ratio : A : B = 5 : 2 B : C = 7 : 13 Solving for A : B : C If A : B = a : b1 and B : C = b2 : c, then A : B : C = ab2 : b1b2 : b1c So, A : B : C = 35 : 14 : 26 Let A, B and C be 35x, 14x and 26x respectively 35x + 14x + 26x = 750 75x = 750 x = 750/75 x = 10 A’s share, 35x = 35*10 = Rs 350 required A’s share = Rs. 350 An alloy contains copper and zinc in the ratio 5 : 3 and another contains copper and tin in the ratio 8 : 5, If equal weights of the two are melted together to form a 3​ rd​ alloy, find the weight of tin per kg in the new alloy? A) 40/129 B) 5/13 C) 5/26 D) 28/5 Correct Answer : 5/26 Explanation : Assume X kg of both the alloys are melted together. weight of copper in X kg of 1st alloy = X* 5/5+3 = 5X/8 kg weight of Zinc in X kg of 1st alloy = X* 3/5+3 = 3X/8 kg Similarly weight of Copper in X kg of 2nd alloy = X* 8/8+5 = 8X/13 kg weight of Tin in X kg of 2nd alloy = X* 5/8+5 = 5X/13 kg both alloy melted together, so total weight= X + X = 2X Weight of tin per kg in total weight = 5X/13 kg / 2X = 5/26 Hence weight of tin in the resulting alloy per kg = 5/26