Thursday, 7 November 2013

Quans-12


Quans - 12


1.       The head of a fish is 6 inches long. Its tail is as long as its head and half its body. If its body is half of its whole length, how long is the fish?

a)      16 inches     b) 24 inches        c) 32 inches          d) 48 inches

Answer:  (d)

Let ‘x’ be the length of the fish. Then we have the following equation:

X = 6 + ½ x + 6 + ¼ x        (Body is ½ x . Tail is 6 + ½ the body ie 6 + ½*1/2x )

Solving the above equation we will get the value of x as 48 inches.

2.       In an examination, there are 100 questions, 4 marks for each correct answer and 2 marks for each wrong answer. If Surya attempted all the 100 questions and scored 40 marks. Find the number of questions he answered wrongly?

a) 30                      b) 40                      c) 70                       d) 60

Answer: (b) Easy to answer from the choice.

Mathematically let ‘x’ be the number of questions answered correctly. Then the number of questions answered wrongly is (100 – x). Now we have an equation

(4*x) – 2*(100-x) = 40. Solving this we get the value of ‘x’ as 40.

3. A candidate appearing for an examination has to secure 40% marks to pass paper 1.But he secured only 40 marks & failed by 20 marks. What is the maximum mark for paper?

a) 100                    b) 200                    c) 150                    d) 180

Answer: (c)  This also could be answered from the choices.
Mathematically he should score 40% to pass the paper. He scored 40 marks and failed by 20 marks. Hence the 40% pass requirement is equal to 40 + 20 = 60 marks. Thus, 40% requirement equals to 60 marks. The total marks (100 %) for the paper is 60 * 100/40 = 150 marks.

4. If the radius of a circle is diminished by 10%, then its area is diminished by?

a) 10%                   b) 19%                  c) 20%                  d) 36%

Answer: (b)

Let the initial radius be 10 units. Then the area is pi*10*10 = 100 pi.

If 10 of radius is reduced  then the new radius is 9 units.

The new area is pi * 9 * 9 = 81 pi. Thus the reduction in area is 19 over earlier 100 ie 19%.

5. If x=y=2z and xyz=256 then what is the value of x?

a) 8                         b) 3                        c) 5                         d) 6

Answer: (a)

X = y = 2z. Hence the value of y = x and the value of z = x/2

Substituting these values then xyz = 256 can be written as x*x*x/2 = 256. ie x3/2 = 256

X3 = 256 * 2 = 512. Hence x = 8

6. If the value of x lies between 0 & 1 which of the following is the largest?

a) x                         b) x^2                   c) -x                       d) 1/x

Answer: (d) 

7. In a journey of 15 miles two-third distance was travelled with 40 mph and remaining with 60 mph. How much time the journey takes?

a) 40 min              b) 30 min             c) 120 min            d) 20 min

Answer: (d)

2/3rd of 15 miles is 10 miles and this distance was travelled at 40 mph.

Hence the time taken to cover this distance is 15 minutes.

Remaining distance of 5 miles was covered at 60 mph. The time taken for this distance is

5 minutes. Thus the total time taken to cover the distance of 15 miles is 15 + 5 = 20 minutes.

8. A man has Rs. 480 in the denominations of one-rupee notes, five-rupee notes and ten-rupee notes. The number of notes of each denomination is equal. What is the total number of notes that he has?

a) 45                      b) 60                      c) 75                       d) 90

Answer: (d)

Since the number of notes for each denomination is equal then let it be ‘x’

Now we have an equation 1*(x) + 5*(x) + 10*(x) = 480. Solving this we get the value of

‘x’ as 30. In other words, the number of notes in each denomination is 30 and adding the three denomination numbers we get the answer as 30+30+30 = 90.  
 
9. A two-digit number is such that the product of the digits is 8. When 18 is added to the number, then the digits are reversed. The number is:

a) 18                      b) 24                      c) 42                       d) 81

Answer: (b) Can be answered from the choice.  ( Please remember that when any two digit number is reversed, then the difference in value between the two numbers will always be a multiple of 9)

10. A sum of money is to be distributed among A, B, C, D in the proportion of 5: 2: 4: 3. If C gets Rs. 1000 more than D, what is B's share?

a) Rs. 500             b) Rs. 1500          c) Rs. 2000           d) None of these

Answer: (c) Simple. C is one part more than D and this equals to Rs 1000.00. B’s share is two parts and hence the amount is 2*1000=Rs 2000


11. A man can complete a journey in 10 hours. He travels first half of the journey at the rate of 21 km/hr and second half at the rate of 24 km/hr. Find the total journey in km.

a) 220 kms           b) 224 kms          c) 230 kms           d) 234 kms

Answer (b) The average speed for the entire trip is given by the formula 2*(xy/x+y) where x and y are the two different speeds. Applying the information given in the question we arrive at the average speed as 22.4 km and since the total distance travelled is for 10 hours the distance covered is 224 kms.

12. In how many different ways can the letters of the word 'CORPORATION' be arranged so that the vowels always come together?

a) 810                    b) 1440                 c) 2880                  d) 50400

Answer: (d) There are 11 letters in the word of which 5 are vowels. These 5 vowels would form a group and thus we have 7 letters ( 11-5 + 1 (group) ). In this 7 letters we have the letter R repeated twice. Hence these 7 letters can be arranged among themselves in 7!/2! Ways. Among the five vowels the letter ‘O’ is repeated thrice. These 5 vowels among themselves can be arranged in 5!/3! Ways.

Thus the total number of arrangement is in 7!/2!* 5!/3! = 50400 ways.


13. A batsman scored 110 runs which included 3 boundaries and 8 sixes. What percentage of his total score did he make by running between the wickets?

a) 45%                   b) 45(5/11)%                      c) 54(6/11)%                       d) 55%

Answer: (b) Runs scored by the batsman in boundaries and sixes is 60 (8*6 + 3*4) The remaining 50 runs out of his total 110 runs were made through running between the wickets.. Hence the percentage of runs acquired through running out of the total runs is

50/110 * 100 = 45 5/11%.


14. 3 pumps, working 8 hours a day, can empty a tank in 2 days. How many hours a day must 4 pumps work to empty the tank in 1 day?

a) 9                         b) 10                      c) 11                       d) 12

Answer: (d) It’s a chain rule sum and apply the principles.

15. Which of the following fraction is greatest of all?

a) 7/8                    b) 6/7                    c) 4/5                     d) 5/6

Answer: (a)

 

 

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