Mathmetics

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

Q71.
Three- tenth of a number is equal to 36% of another number. If the sum of these two numbers is 88, then what is the value of the smaller number ?
1) 38 2) 40
3) 48 4) 56
5)None of these
Answer : 40
Explanation :
Let, one number be x.
The other number = (88 - x)
                x x 3/10 = (88 - x) x 36/100
= 30x = 3168 - 36x
x = 3168/66 = 48
The smaller number = 88 - 48 = 40
View Answer

Q72.
If the total cost of four tube-lights and three bulbs is Rs. 260 and the ratio between the cost of a  tube-lights and a bulb is 5 : 2 respectively. What is the total cost one tube-light and six bulbs ?
1) Rs. 210 2) Rs. 130
3) Rs. 180 4) Rs. 170
5)None of these
Answer : Rs. 170
Explanation :
Let, the C.P. of 1 tube light be Rs.5x
C.P. of 1 bulb = Rs. 2x
4 x 5x + 3 x 2x = 260
x = 260/26 = 10
C.P. of 1 tube light and 6 bulbs 
= 5 x X + 6 x 2 xX
= 5 x 10 + 12 x 10 = Rs.170
View Answer

Q73.
Alok spends 23% of an amount of money on an insurance policy, 33% on food, 19% of children’s education and 16% on recreation. He deposits the remaining amount of Rs. 504 in bank. How much total amount did he spend on food and insurance policy together ?
1) Rs.3200 2) Rs.3126
3) Rs.3136 4) Rs.3048
5)None of these
Answer : Rs.3136
Explanation :
Let, the total amount of money with Alok be Rs.x .
x = (504 x 100)/[100 - (23+33+19+16) ]= Rs. 5600
Reqd. amount of money
= ( Rs. 5600 x 56)/100= Rs. 3136
View Answer

Q74.
The sum of the present ages of Ram, Shyam and Vijay is 72 years. Also the sum of present ages of Ram and Shyam is 42 years. What is the present age of Vijay ?
1) 30 yrs 2) 24 yrs
3) 18 yrs 4) 36 yrs
5)None of these
Answer : 30 yrs
Explanation : The present age of Vijay = 72 - 42 = 30 years
View Answer

Q75.
A some of money at compound interest amounts to thrice itself in three years. In how man years will it be nine times itself ? 
1) 4 years 2) 6 years
3) 8 years 4) 12 years
5)None of these
Answer : None of these
Explanation : Let, principal be x.It will be 3x after  years.
9x will takes another 3 years.
So,total time taken= 3+3 = 6 years.


Short-cut method:

x     ------  3x in 3 years 
9x i.e. (3x)2   = 3 X 2 = 6 years. 
View Answer

Q76.
Two numbers are such that their difference, their sum and their product are in the ratio 1:7:24 respectively. What is the product of the two numbers ?
1) 12 2) 24
3) 36 4) 48
5)None of these
Answer : 48
View Answer

Q77.
The income of A,B and C together is Rs.14500 and they spend  60%,65% and 70% of their income respectively. If their savings are in the ratio 14:21:15 . What is the income of  B ?
1) Rs.4000 2) Rs.4800
3) Rs.5600 4) Rs.6000
5)None of these
Answer : Rs.6000
Explanation : We know that, income - expenditure = saving
Let, their income are 100% individually. 
So, A's saving = 100 - 60= 40% ; B's saving = 100 - 65= 35% ; C's saving = 100 - 70= 30%
But their saving ratio are 14:21:15.
Then, A's income , 40% = 14 or 100% =( 14/40) x 100 = 35
B's income , 35% = 21 or 100% =( 21/35) x 100 = 60
C's income , 30% = 15 or 100% =( 15/30) x 100 = 50
So, 35x + 60x + 50x = Rs.14500
or 145x = Rs.14500
or x = 100
Therefore income of B= 100x60 = Rs.6000.
View Answer

Q78.
In a school, 3/7 of the students are girls and the rest are boys. 1/4 of the boys are below ten years of the age and 5/6 of the girls are also below ten years of age. If number of students above ten years of age is 500 , find the total number of students in the school ?
1) 1000 2) 1200
3) 1400 4) 2000
5)None of these
Answer : 1000
Explanation : Let, total numbers of students are x.
Girls = 3x/7. and boys = 1 - 3x/7 = 4x/7.
Below 10 years boys = (4x/7) 1/4 = 4x/28 = x/7
The girls are also below ten years of age = (3x/7) 5/6 = 5x/14
So, above ten years = x - (x/7 + 5x/14) = x- x/2 = x/2 
Given, x/2= 500 
or x = 1000.

View Answer

Q79.
A vendor sells 20 articles and gets a profit which is equal to cost price of 4 articles. What is his percentage of profit in this transaction ?
1) 20 % 2) 24 %
3) 25 % 4) 33.33 %
5)None of these
Answer : 20 %
Explanation :  Let, C.P of each article is Rs.1/.
So, C.P of 20's articles = Rs.20/ and C.P of 4's articles = Rs.4/  i.e. profit 
We know that,  S.P = C.P + Profit = 20 + 4 = Rs. 24/ 
Therefore, % of profit = (4/20) x 100 = 20%
View Answer

Q80.
A vendor sells 20 articles and gets a profit which is equal to selling price of 4 articles. What is the percentage of profit in this transaction ?
1) 20 % 2) 24 %
3) 25 % 4) 33.33 %
5)None of these
Answer : 25 %
Explanation : Let, S.P of each article is Rs.1/.
So, S.P of 20's articles = Rs.20/ and S.P of 4's articles = Rs.4/ i.e. profit 
We, know that C.P = S.P -Profit = 20 - 4 = Rs. 16/ 
Therefore, % of profit = (4/16) x 100 = 25%
View Answer