Jake is faster than paul.Jake and paul each walk 24km.The sum of their speed is 7km/h and the sum of times taken by them is 14hours. then jakes speed is equal to

a)3kmph
B)7kmph
C)4kmph
D)5kmph

• suppose,
  speed of jake is x then speed of paul is 7-x.
  each of them walk 24km.
  so, time taken by jake is 24/x and time taken by paul is 24/(7-x).
  again,(24/x)+(24/(7-x))=14
  (7-x)*24 + 24*x =14*x*(7-x)
  7*24-14*x*(7-x)=0
  x^2-7x+12=0
  so,(x-4)(x-3)=0
  so,x=3 or 4
  if x=3 then speed of paul is 4
  similarly if x=4 then speed of paul is 3
  as jake is faster than paul, so speed of jake is 4.
• 9 years agoHelpfull: Yes(22) No(0)
• Just go to the Options and see the sum of whose speed is equal to 7km/hr
  as it is the sum of jake n paul speed.
  it is 4+3=7 but as it is given , jake is faster the answer is 4
• 9 years agoHelpfull: Yes(5) No(1)
• opt C
  24/x + 24/(7-x) = 14
• 9 years agoHelpfull: Yes(3) No(2)
• jake speed=x, paul speed=7-x
  total time=14 hours
  24/x+24/(7-x)=14
  x=4, 3
  jack is faster than paul
  speed of jakes will be 4 km/hr
• 9 years agoHelpfull: Yes(3) No(0)
• option c.
  first we cancel the option of 7 kmph.
  now we r left with 3 options only.
  cancel 5 kmph as it is giving fraction.
  left with two options only.
  jake is faster ,so c is the answer.
  
• 9 years agoHelpfull: Yes(2) No(0)
• given sum of speed is 7 so
  all possible combination of 7 is
  1+6=7
  2+5=7
  3+4=7
  (1,6)and (2,5) are irrelevant because sum of time is 14
  so answer is (3,4)
  jake is faster so ans is 4kmph
• 9 years agoHelpfull: Yes(1) No(1)
• Jakes speed is 4kmph.
• 9 years agoHelpfull: Yes(0) No(0)
• let j=xkm/h, p=ykm/h so, x+y=7 and 24(1/x+1/y)=14 or (x+y)/xy=14/24 or xy=12
  now(x-y)^2=(x+y)^2-4xy=1
  now x+y=7------1
  x-y=1-------2 by caculating eqn1 and eqn 2 we will get x=4 and y=3 so jakes speed is 4km/h
  
• 9 years agoHelpfull: Yes(0) No(0)
• opt C - 4kmph
  24/x + 24/(7-x) = 14
• 9 years agoHelpfull: Yes(0) No(0)