Thursday, 13 August 2015

Solutions for Ages


1.       Consider  fathers age= f ,sons age = s
       Given f=3*s +s = 4s           ----1
       f+8 =5/2 *(s+8)                  ----2
       f+16=x *(s+16)
      From 1 and 2 we can say that
      4s+8=5/2(s+8) => (4s+8)*2 = 5s+40
      => 8s+16=5s+40 =>3s=24 =>s=8
     Therefore f=4*8=32 => f+16= 48 and s+16=24
      48 = x *24 =>x= 48/24 => 2 times

2.      Consider age of younger child = x
      Then( x)+(x+3)+(x+6)+(x+9)+(x+12)=50
       5x+30=50 => 5x=20 => X=4
      Therefore youngest child is 4years

3.      F=38 and F=2s => s=19
      Sons age before 5 years = 19-5 = 14years

4.      A=B+2
      B=2C => C = B/2
      A+B+C= 27 =>B+2+B+B/2=27 => B=10

5.      S: A=5: 4 => S=5X ,A=4X
      S+3: A+3=11:9 => S+3=11Y, A+3=9Y
      5X=11Y-3, 4X=9Y-3 Solving them we get y=3
      A+3=9Y => A=9*3-3=27-3=24

6.      M=24+S and M+2=2(S+2)
      Solving them 2S+2=24+S => S=22Years

7.   K-6: S-6=6: 5 => K=6X+6, S=5X+6
      K+4: S+4=11: 10=> K=11Y-4, S=10Y-4
      =>6X-11Y+10=0, 5X-10Y+10=0
      Solving them we get Y=2
      S=10Y-4 = 10*2-4 = 20-4 =16Years

8.  F+S=60
     F-6=5(S-6) =>F-6=5S-30 => F=5S-24
     From the above two equations 5S-24+S=60 => 6S=84 =>S =14
     Therefore after six years S=14+6=20years

9.   A: D = 4:3 =>A= 4X B=3X
      A+6=26 => A=20
      20=4X So X=5 Therefore D=3*5=15 Years

10.  S=R-7
       S: R=7:9 => S=7X, R=9X
       7X=9X-7 =>X=7/2
       S= (7)*(7/2) = 24.5Years

11.  A: B: C= 4: 7: 9 
       => A=4X, B=7X, C=9X
        (A-8) + (B-8) + (C-8) = 56 => A+B+C=80
        4X+7X+9X=80 => X=4
        So A = 4*4 = 16, B = 7*4 = 28, C = 9*4 = 36

12.  F= 38+A
       M=36+B
       B=A-4 => M= 36+A-4 => M=32+A
       So F-M = 38+A-32-A =6Years

13.  P = (2/5)*M => 5P=2M
       (P+8)=1/2(M+8) => 2P+16=M+8 => 2P+8=M
       Solving them we get 5P=2(2P+8) => P=16 So M=16*5/2 =40Years

14. Data not sufficient to solve

15.  F-10 =3(S-10) => F=3S-20
       F+10=2(S+10) => F=2S+10                                                                                                              
   ð  3S-20=2S+10 =>S=30 And F=70
   ð  So F: S= 7:3



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