1Which is the least number which must be subtracted from 4573, so that the remainder is a perfect square ? 53 84 61 36
2.If (x-4)/7 + (7-2x)/6 = (8-x)/2 , then x= ? 9 7 11 2
3.Sand and cement were mixed in the ratio 3 : 1 to make up 1 tonne. How much sand must be added to make the ratio 6 : 1 ? 1 tonne 750 kg. 500 kg. 1.5 tonne
5.Five years ago the average age of a family of six members was 20 years. A baby is born and now the average age is 22 years. How old is the baby at present ? 2 years 5 years 3 years 4 years
Two trains 246m and 304m long are travelling towards one another at 114km/hr and 66km/hr respectively. How long do the trains take to pass one another? 13sec 12sec 11sec 9sec
How many prime factors are there in the expression (6)23 x (4)10 x (5)10 ? 7 76 3 9

• 1) Check for all the nos.
  4573 - 53 = 4520
  4573 - 84 = 4489
  4573 - 63 = 4512
  4573 - 36 = 4537
  No perfect squares ll end in 2 nd 7 nd 0 should also be neglected since perfect sq. has atleast 2 0's at d end...... So dont consider 1st, 3rd nd 4th case... Calculate sq. root for 2nd case... The nearest perfect square is 3600 which is square root of 60... So values result should be greater than 60...
  Hence 4489 is the perfect square... 84 must be subtracted...
  Ans : 84
  
  2)(x-4)/7 + (7-2x)/6 = (8-x)/2
  (6x-24+49-14x)/42 = (8-x)/2
  50-16x = 336-42x
  26x = 286
  x = 11
  Ans : 11
  
  3) Let amount of sand nd cement be 3x nd x
  3x+x = 1000kg
  x = 250
  Sand : cement => 750 : 250
  (750+y)/250 = 6/1
  y = 750
  Ans : 750
  
  6)114 km/h => 114*5/18 m/s => 95/3 m/s
  66km/h => 66*5/18 m/s => 55/3 m/s
  Time taken = (246+304)/(55/3 + 95/3) => 11 sec
  Ans : 11 sec
  
  7) (6)23 x (4)10 x (5)10
  2*3*23*2*2*2*5*5*2*5
  => 2^5 * 3^1 * 5^3
  => 5+1+3 = 9 [If 23 is not considered as d prime factor...Otherwise it ll be 10]
  Ans : 9
  
  
• 10 years agoHelpfull: Yes(43) No(1)
• 5) Let d age of all the 6 people be 20...
  After 5 years i.e. now their ages ll be 25...
  Total age of all the 6 now is 25*6 = 150
  Including baby's age, avg is 22... Let x be the age of baby...
  (150+x)/7 = 22
  x = 4
  Ans : 4 years
• 10 years agoHelpfull: Yes(19) No(1)
• babies age is 4 years
  
• 8 years agoHelpfull: Yes(1) No(0)
• 1.ans is 36
  2.ans is 11
  3.ans is 1 tonne
  5.ans is 5 year
  13 sec
  23
• 10 years agoHelpfull: Yes(0) No(14)
• please explain why 3x+x=1000???? why it is not 3x+x=750
• 8 years agoHelpfull: Yes(0) No(0)
• because 1 tonne=1000kg, so we take 3x+x = 1000
• 8 years agoHelpfull: Yes(0) No(0)
• (x-4)/7 + (7-2x)/6 = (8-x)/2
  
  (6x-24+49-14x)/42 = (8-x)/2
  
  => 50-16x = 336-42x
  
  => 26x = 286
  
  => x = 11
• 5 years agoHelpfull: Yes(0) No(0)