Mathmetics

ISBT Mathmetics for all banking PO,Clerk,IBPS PO,Railway,SSC,IAS,OAS Exams

Q541.
In how many different ways can the letters of the word 'DETAIL' be arranged in such a way that the vowels occupy only the odd positions ?
1) 24 2) 32
3) 36 4) 48
5)None of these
Answer : 36
Explanation :
There are 6 letters in the given word, out of which there are 3 vowels and 3 consonants.

Let us mark these positions as under:

(1) (2) (3) (4) (5) (6)

Now, 3 vowels can be placed at any of the three places out 4, marked 1, 3, 5.

Number of ways of arranging the vowels = 3P3 = 3! = 6.

Also, the 3 consonants can be arranged at the remaining 3 positions.

Number of ways of these arrangements = 3P3 = 3! = 6.

Total number of ways = (6 x 6) = 36.

View Answer

Q542.
How many 3-digit numbers can be formed from the digits 2, 3, 5, 6, 7 and 9, which are divisible by 5 and none of the digits is repeated ?
1) 6 2) 10
3) 12 4) 20
5)None of thse
Answer : 20
Explanation :
Since each desired number is divisible by 5, so we must have 5 at the unit place. So, there is 1 way of doing it.
The tens place can now be filled by any of the remaining 5 digits (2, 3, 6, 7, 9). So, there are 5 ways of filling the tens place.
The hundreds place can now be filled by any of the remaining 4 digits. So, there are 4 ways of filling it.
So, required number of numbers = (1 x 5 x 4) = 20.
View Answer

Q543.
In how many different ways can the letters of the word 'CORPORATION' be arranged so that the vowels always come together ?
1) 810 2) 1440
3) 2880 4) 50400
5)57600
Answer : 50400
Explanation :
In the word  'CORPORATION', we consider the vowels OOAIO as one letter.
Thus, we have CRPRTN (OOAIO).
This has 7 (6 + 1) letters of which R occurs 2 times and the rest are different.
Number of ways arranging these letters =7!/2! = 2520.
Now, 5 vowels in which O occurs 3 times and the rest are different, can be arranged in 5!/3!= 20 ways.
So, required number of ways = (2520 x 20) = 50400.
View Answer

Q544.
In how many different ways can the letters of the word 'LEADING' be arranged in such a way that the vowels always come together ?
1) 360 2) 480
3) 720 4) 1280
5)None of these
Answer : 720
Explanation :
The word 'LEADING'' has 7 different letters.

When the vowels EAI are always together, they can be supposed to form one letter.

Then, we have to arrange the letters LNDG (EAI).

Now, 5 (4 + 1 = 5) letters can be arranged in 5! = 120 ways.

The vowels (EAI) can be arranged among themselves in 3! = 6 ways.

 So, required number of ways = (120 x 6) = 720.
View Answer

Q545.
From a group of 7 men and 6 women, five persons are to be selected to form a committee so that at least 3 men are there on the committee. In how many ways can it be done ?

1) 565 2) 664
3) 742 4) 756
5)None of these
Answer : 756
Explanation :


View Answer

Q546.
A sum fetched a total simple interest of Rs. 4016.25 at the rate of 9 p.c.p.a. in 5 years. What is the sum ?

1) Rs. 4462.50 2) Rs. 8032.50
3) Rs. 8900 4) Rs. 8925
5)None of these
Answer : Rs. 8925
Explanation :
Principal = (100 x 4016.25 ) / ( 9 x 5) = Rs. 8925.

View Answer

Q547.
A sum of money at simple interest amounts to Rs. 815 in 3 years and to Rs. 854 in 4 years. The sum is:
1) Rs. 650 2) Rs. 690
3) Rs. 698 4) Rs. 700
5)None of these
Answer : Rs. 698
Explanation :
S.I. for 1 year = Rs. (854 - 815) = Rs. 39.
S.I. for 3 years = Rs.(39 x 3) = Rs. 117.
Principal = Rs. (815 - 117) = Rs. 698.
View Answer

Q548.
A sum of Rs. 1550 is lent out into two parts, one at 8% and another one at 6%. If the total annual income is Rs. 106, find the money lent at each rate ?     
1) Rs. 800 2) Rs. 900
3) Rs. 1100 4) Rs. 870
5)None of these
Answer : Rs. 900
Explanation :
Let the sum lent at 8% be Rs. x and that at 6% be 
Rs. (1550 - x).
        or (X x 8 x 1/100 ) + [ {(1500- X) x 6 x 1}/ 100 ] = 106
or 8 x + 9300 - 6 x = 10600
or 2 x = 1300 
or x = 650
Money lent at 8% = Rs.650. 
Money lent at 6% = Rs(1550 - 650) = Rs. 900

View Answer

Q549.
A sum was put at S.I. at certain rate for 5 years. Had it been put at 4% higher rate, it would have fetched Rs. 60 more. What was the sum ?
1) Rs.280 2) Rs.300
3) Rs.320 4) Rs.400
5)None of these
Answer : Rs.300
Explanation :
Let Principal =P, Rate of Interest = R
Given, T = 5  So, (P x 5 x R) / 100 
Now new rate of interest =( R+ 4) %
So, S.I. =  {P  x 5 x (R+ 5%) } / 100 
Then,  {P  x 5 x (R+ 5%) } / 100 - (P x 5 x R) / 100  = 60
 or P /60 = 5   or  P= Rs. 300
View Answer

Q550.
Pipes A and B running together can fill a cistern in 6 min. If B takes 5 min more than A to fill the cistern, then the times in which B will fill the cistern separately will be respectively.

1) 12 min 2) 15 min
3) 18 min 4) 20 min
5)None of these
Answer : 15 min
Explanation :
Let pipe A fills the cistern in x minutes.
Therefore, pipe B will fill the cistern in (x + 5) minutes.
1/x + 1/x+1 = 1/6
        or  x = 10
Hence pipe  B can fill the cistern in 10 +5 = 15 min.
View Answer