Ratio and Proportion

Q 1: If 40% of a number is equal to two-third of another number, what is the ratio of first number to the second number? A)2:8 B)5:3 C)4:5 D)5.9 Answer : Option B Explanation: Let 40% of A=(2/3)B then,40A/100=2B/3 =>2A/5=2B/5 =>A/B=[2/3x5/2]=5/3 A:B=5:3 Q 2: Find the fourth Proportion to 3.4, 4.6 and 8.6? A)12.163 B)8.9 C)10.5 D)11.63 Answer : Option D Explanation: Fourth proportional = (b × c)/a a=3.4, b=4.6, c=8.6 =>(4.6x8.6)/3.4=11.63 Q 3: If a:b=1:4 and b:c=3:4 find a:b:c? A)3:16:8 B)2:11:11 C)3:12:16 D)4:17:20 Answer : Option C Explanation: a:b = 1:4 b:c = 3:4 a = 1 × 3 = 3 b = 4 × 3 = 12 c = 4 × 4 = 16 (a = a × b, b = b × b and c = b × c) a:b:c = 3:12:16 Q 4: A sum of money is to be distributed among A, B, C, D in the proportion of 5 : 2 : 4 : 3. If C gets Rs. 1000 more than D, what is B's share? A)Rs.2200 B)Rs.1000 C)Rs.2000 D)Rs.2500 Answer : Option C Explanation: Let the shares of A, B, C and D be Rs. 5x, Rs. 2x, Rs. 4x and Rs. 3x respectively. Then, C-D=1000 =>4x - 3x = 1000 =>x = 1000. B's share = Rs.2x = Rs.(2 x 1000) = Rs.2000. Q 5: The fourth proportional to 4, 8, 16 is: A)17 B)32 C)20 D)None of these Answer : Option B Explanation: Let the fourth proportional to 5, 8, 15 be x. Then, 4 : 8 : 16 : x 4x = (8 x 16) x=(8x16)/4=32

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