32
Q:

# The third proportional to$x2-y2$ and $x-y$ is :

 A) (x + y ) B) (x - y) C) (x + y) / ( x - y) D) (x -y) / ( x + y)

Answer:   D) (x -y) / ( x + y)

Explanation:

Let the third proportional to $x2-y2$ and $x-y$ be z. Then,

$x2-y2:x-y::x-y:z$

$=>x2-y2*z=x-y2$

=> z=$x-y2x2-y2=x-yx+y$

Q:

One year ago the ratio between Maneela’s and Shanthi’s salary was 3 : 4. The ratios of their individual salaries between last year’s and this year’s salaries are 4 : 5 and 2 : 3 respectively. At present the total of their salary is Rs. 4160. The salary of Maneela, now is?

 A) Rs. 1600 B) Rs. 1700 C) Rs. 1800 D) Rs. 1900

Explanation:

Let the salaries of Maneela and Shanthi one year before be M1, S1 & now be M2, S2 respectively.

Then, from the given data,

M1/S1 = 3/4  .....(1)

M1/M2 = 4/5 .....(2)

S1/S2 = 2/3  .....(3)

and M2 + S2 = 4160  .....(4)

Solving all these eqtns, we get M2 = Rs. 1600.

18 3405
Q:

The ratio of Pens and Pencils in a shop is 3 : 2 respectively. The average number of Pens and Pencils is 180. What is the number of Pencils in the shop?

 A) 444 B) 344 C) 244 D) 144

Explanation:

Given ratio of pens and pencils = 3 :2

Number of Pens = 3x

Number of Pencils = 2x

Average number of pencils & Pens =  180

5x = 360

=> x = 72

Hence, the number of pencils = 2x = 72 x 2 = 144.

18 2949
Q:

The ratio of boys and girls in a school is 9:5.If the total number of students in the school is 1050.Then number of boys is

Let the ratio be 'R'

Total number of students = 1050

Then,

9R + 5R = 1050

14R = 1050

=> R = 75

Hence, the number of boys = 9R = 9 x 75 = 675

3708
Q:

3 : 12 :: 5 : ?

 A) 17 B) 30 C) 26 D) 32

Explanation:

22 3034
Q:

The ratio of the incomes of Pavan and Amar is 4 : 3 and the ratio of their expenditures are 3:2. If each person saves Rs. 1889, then find the income of Pavan?

 A) 6548 B) 5667 C) 7556 D) 8457

Explanation:

Let ratio of the incomes of Pavan and Amar be 4x and 3x

and Ratio of their expenditures be 3y and 2y

4x - 3y = 1889 ......... I

and

3x - 2y = 1889 ...........II

I and II

y = 1889

and x = 1889

Pavan's income = 7556

15 3399
Q:

Maneela lent Rs. 8000 partly at the rate of 5% and partly at the rate of 6% per annum simple interest. The total interest she get after 2 years is Rs. 820, then in which ratio will Rs. 8000 is to be divided?

 A) 7:1 B) 13:5 C) 15:7 D) 2:7

Explanation:

Maneela lent Rs. 8000 in two parts,

15 2776
Q:

The ratio of male and female in a city is 7 : 8 respectively and percentage of children among male and female is 25 and 20 respectively. If number of adult females is 156800, what is the total population of the city?

 A) 4,12,480 B) 3,67,500 C) 5,44,700 D) 2,98,948

Explanation:

Let the total population be 'p'

Given ratio of male and female in a city is 7 : 8

In that percentage of children among male and female is 25% and 20%

=> Adults male and female % = 75% & 80%

But given adult females is = 156800

=> 80%(8p/15) = 156800

=> 80 x 8p/15 x 100 = 156800

=> p = 156800 x 15 x 100/80 x 8

=> p = 367500

Therefore, the total population of the city = p = 367500

29 4744
Q:

Two numbers are in the ratio 3 : 7. If 6 be added to each of them, then they are in the ratio 5 : 9. Find the numbers ?

 A) 11 & 17 B) 7 & 17 C) 9 & 21 D) 13 & 23

Explanation:

Let the two numbers be x and y

Given x : y = 3 : 7 .....(1)

Now, x+6 : y+6 = 5 : 9 .....(2)

From (1), x = 3y/7

From (2), 5y - 9x = 24

=> 5y - 9(3y/7) = 24

=> y = 21

=> From(1), x = 9

Hence, the two numbers be 9 and 21
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