Ratio & Proportion Set 1 

1. Find out the third proportion of the term 12 and 24
   A)38
   B)44
   C)48
   D)42
   
   C)48
   Explanation :
   12:24 :: 24 : ?
   ? = (24*24)/12 = 48
   
   
   
2. If a:b = 2:3, b:c = 6:5 and c:d = 3:5 then find the value of a:b:c:d
   A)18:25:12:18
   B)12:18:15:25
   C)25:18:15:12
   D)12:25:18:25
   
   B) 12:18:15:25
   Explanation :
   a:b = 2:3 = 12:18
   b:c = 6:5 = 18:15
   c:d = 3:5 = 15 :25
   a:b:c:d = 12:18:15:25
   
   
   
3. If x:y = 4:7, the  value of (x2 + y2) /(x2 – y2) = ?
   A)-33/65
   B)65/33
   C)33/65
   D) -65/33
   
   D) -65/33
   Explanation :
   X = 4a; y = 7a
   (x2 + y2) /(x2 – y2) = (4a)2 + (7a)2/ (4a)2 – (7a)2
   = a2(16+49)/ a2(16-49)
   = -65/33
   
   
   
4. The ratio of boys and girls in the school is 7:9 when 22 new boys  are joined in this school  then the ratio become 9:10.How many girls in this school ?
   A)180
   B)200
   C)160
   D)220
   
   A)180
   Explanation :
   7x+22/9x = 9/10
   70x+220 = 81x
   11x = 220
   X =20
   20*9 = 180 girls(7B:9G)
   
   
   
5. Two numbers are in the ratio of 5:8 .If 4 is subtracted from each then the ratio become 1:2.The small number is
   A)16
   B)4
   C)10
   D)2
   
   C)10
   Explanation :
   5x-4/8x-4 = ½
   10x-8 = 8x-4
   2x = 4
   X=2
   5(2) = 10
   
   
   
6. x:y = 7:4 then (4x+7y) : (7x+4y)
   A)65:56
   B)56:65
   C)34:45
   D)13:18
   
   B)56:65
   Explanation :(4(7)+7(4)) : (7(7)+4(4)) = 56:65
   
   
   
7. The sum of present age of 2 persons is 100yrs.Before 5 years the ratio of their ages is 5:13.Find the age of younger person
   A)15
   B)20
   C)25
   D)30
   
   D)30
   Explanation :
   From option
   30+70 = 100
   25:65 = 5:13
   
   
   
8. The ratio of monthly income of A and B in the ratio is 6:5 and the ratio of their expenditure is 9:7.If each saves Rs.1500.Then the sum of their salary is
   A)11,000
   B)9,000
   C)1,0000
   D)12,000
   
   A)11,000
   Explanation :
   4500:3500 – e
   1500:1500 – s
   6000 + 5000 = 11000
   
   
   
9. What number should be added or subtracted from each term in the ratio 11:9 so that it become 6:5
   A)+4
   B)-4
   C)-5
   D)-3
   
   A)+4
   Explanation :
   44:36
   Add 4
   48:40 = 6:5
   
   
   
10. The ratio of two persons A and B salaries in the ratio 12:7 if 12% increased salary yearly then what will be the B Salary after 2 yrs.
    A)7808
    B)8700
    C)7,500
    D)8781
    
    D)8781
    Explanation :
    12:7 = 12,000 : 7,000
    12% =  B = 840……1st yr and B = 941 …..2nd yr
    New inc B  = 7000+840+941 = 8781