Answer Key Maths 1-25 LGO Examinatio 2012         Q1  If  the radius of circle 7  cm  then   the area of  circle  is 153.86  CM  Square    Q2  A  taxpayer   is exempted  of income tax for  the first  Rs 40000.00 of his annual  income  and for rest of income  he has to pay  tax at the rate  of 20 % . If he  pays  Rs 3160 annually  as income tax find his  monthly  income A    4850    B  4650   C.   4550     D.  None  of  these Correct Answer   D  None  of  these Explanation   :  Let  the  annual  income of Tax prayer  is  ( x+40000) Then   x *20/100= 3160 *12 X=5*3160=  Rs  15800/-    Then annual  income  of tax  payer 40000+15800   =  55800/-  So   monthly  income   is      55800/12    =  4650/-  Hence Correct  answer   is   B  4650/-   Q3  The  perimeter  of an  isosceles  triangle  is 42 cm  and its base is  1  ½  times  each of  the equal side  of the triangle  A.      12 cm, 12 cm  18  cm B.       6 cm 6  cm 9  cm C.       18 cm, 18 cm 24 cm D.      None of  these Correct  Answer   A .   12 cm, 12 cm  18  cm Explanation  Given, perimeter of an isosceles triangle = 42 cm Let the equal  side of triangle be x cm Base of triangle =   x So, perimeter = 42 cm So, the length of each side of the triangle is 12cm, 12cm and 18cm respectively. Q4   Find the  total surface area  of a cylinder  having  radius  of the base  14 cm  and height  30 cm A.      3872 cm2 B.      4872 cm2 C.       3782 cm2 D.      None  of  these Q 5   When  the fractions  9/11 , 8/10 7/9  7/11 arranged  in the  ascending  order of  value  the result is A .  7/11  8/10 7/9  9/11 B.  9/11 8/10  7/9  7/11 C.  7/11  7/9  8/10  9/11 D.  8/10  7/11  9/11  7/9 Correct   Answer   C  .  7/11  7/9  8/10  9/11 Q6  How many  cubes  of 3 cm edge can be cut  out of cube  of 18 cm edge A  216  B  516  C  36  D  None of  these Correct  Answer   A  216 Q7  A reduction  of 10  %   in the price of sugar  enables  a shopkeeper  to obtain  25  kg  more  for  2250 The original  price  per kg  A    8 B   9 C  10 D  11 Correct Answer    9 Q8  The cost price of  19 mangos  is equal  to the selling price of 16 mangoes . The gain  percent is A  3 9/17 % B  15  15/19 % C   18 ¾  % D  20  % Correct  Answer   D  20  % Q9  A  train travelled  distance of 10 KM , 20 KM  and 30 KM  at speeds  of 50  KM . 60 KM and 90  KM respectively . The average speed  of the  train  in (KM/Hour) was A.      66.67         B  60          C   69.23          D None of These Correct   Answer  A 66.67 Q10  Find smallest number  which  is divisible  by  12 , 15,20  and  is perfect square A  400 B 180  C 900 D 1000 Correct Answer    C  900 Explanation Find  LCM of  12, 15  and 20 12  -  2*2*3 * 15 =  3*5 20= 2*5  LCM = 2*2*3*3*5   (  2 and 3  have  their  pairs  and  5 has no  pair   to make  a perfect square  LCM is  multiply  with  5 Ie  2*2*3*3*5*5= 900 Q11  if 6 men can do  a piece  work in 20 days  and one man can do   the work of two boys  then  in how many days  can  10 men and  5 boys  do the same work  A 8 B 10 C 12 D None of these Q12   A train length  150 m   takes  40.5 seconds  to cross the tunnel  of length 300 m . The speed of train (in  KM/HR)  is A 13. 33 B  26.67 C  40 D  400 Correct  Answer   C 40 Q13  if   the number  is multiplied  by  three  fourth  of itself   thus  obtained  is 10800.  What is that number A  210 B  189 C 120 D  160 Correct  Answer  C  : 120  120*3/4  =  90 120*90=10800 Q14  If  the  three fourth   of number  is subtracted  from  the number , the value  so obtained  is 163 What  is that number A  625 B  562 C 632 D 652 Correct answer   D 652  652*3/4  = 489    so   652-489  = 163 Q15   In a division sum   a student  took   63 as  divisor  instead of  36 .  His answer  was 24 The correct answer   is   A  36 B  42 C 32 D  None of  these Correct  Answer  B  42   X/63  =24     63*24= 1512      Then  1512/36= 42 Q16   Which of  the following  statement is a true  statement A    and  22  /7   are  both  rational  B    and  22  /7   are  both irrational C   and  is rational  and  22  /7   irrational D  and  is irrational  and  22  /7   rational   Q17   If  one kilometer  is  equal  to   10  hectometer  then 1 hectometer  is equal to  A      10  decameters B      1  deca meter C      100  decameters D    10   Decimeters 1 hecto meter is equal to 100 meters, as is 10 decameters So  correct  answer   A Q18   The  average of  8  numbers  taken   together is 12 .  Two of these  numbers  are 0  and the remaining numbers are equal  .  What is  the value  of  the  non zero  number A  12  B  14 C  16 D 18 12*6+0+0=  72/8  =  9 14*6+0+0=  84/8 = 10.5 16*6+0+0= 96/8  =  12  18*6+0+0 =  108/8=  13.5   So  the correct answer   is   C  16 Q19  The average salary of all workers in a workshop is Rs 850/- There are seven technicians whose average salary is Rs 1000/- and average salary of other is Rs 780/- what is the total number of workers in the workshop. A  18 B 20 C 21 D 22 Correct   Answer   D 22 Q20  A sum of Rs 8500/- is to be divided among 5 men, 6 women and 8 boys in the ratio of 10:7:1 . the share of one woman will be A 85 B 385 C 595 D 850               Correct Answer   85 Q21 Gudia purchased a watch at 9/10th  of its selling price and sold it at 8% more that it selling price. Her gain is A 18 % B  20 % C 10  % D None of  these Q22  A fruit seller  had some apples. He sells 40% apples and still has 420 apples. Originally, he had. A 588   apple B 600 apple C  672  apple D  700 appl e C orrect   answer   D  700  Apple Q23   In the first 10 overs of a cricket game, the run rate was only 3.2 . What should be the run rate in the remaining 40 overs to reach the target of 282 runs A  6.25 B  6.5 C 6.75 D  7 Correct  Answer   A 6.25 Q24  How much time will it take for an amount of  Rs 450 to yield Rs 81 as interest at 4.5% per annum of simple interest A 3.5 B   4 C  5 D  4 Correct  Answer  D   4 Years Q25 The ratio between the length and the breadth of a rectangular park is 3:2 if a man cycling along the boundary of the park at the speed of 12 km/hr completes one round in 8 minutes, the  park (in sq. m) is A   15360   B  153600 C  30720 D  None of these Correct  Answer  A 15360 Dear  readers    Please  post your comment  about the answer of questions Disclaimer This key has no concerned with the Department of  Posts or any other examination nodal agency.