EXERCISE 7A (OBJECTIVE TYPE QUESTIONS IN 26 30 SOLUTION )

26.       Three numbers are in the ratio of 3 : 4 : 6: and their product is 1944. The largest of these numbers is:

a)      6

b)      12

c)       18

d)      None of these

27.       Two numbers are such that the square of one is 224 less than 8 times the square o the other. If the numbers be in the ratio of 3: 4: 4, the numbers are:

a)      6,8

b)      9,12

c)       12,16

d)      None of these

28.       Tow numbers are such that the ratio between them is 4: 7. If each I increased by 4, the ratio becomes 3: 5. The larger number is:

a)      36

b)      48

c)       56

d)      64

29.       The sum of three numbers is 264. If the first number be twice the second and third number be one- third of the first, then the second number is:

a)      48

b)      54

c)       72

d)      84

30.       The sum of two numbers is 22. Five times one number is equal to 6 times the other. The bigger of the two numbers is:

a)      10

b)      12

c)       15

d)      16

  ANSWERS

 26. C

 27. A

 28. C

 29. C

 30.B

SOLUTION

26.       Let the numbers be 3X, 4X and 6x.

Then, 3X x 4X x 6X = 1944      72X³ = 1944       x³ = 27   X = 3.

 Largest number = 6X = 18.

27.       Let the numbers be 3X and 4X. then,

 (4X)² = 8 x (3X)² - 224    16X² = 72 X² - 224      56x² = 224     x² = 4        X = 2.

So, the numbers are 6 and 8.

28.       Let the numbers be 4X and 7X. Then, 4X + 4 / 7X + 4 = 3/5    5 (4X + 4) = 3 (7X + 

4)     X = 8.

Larger number = 7X = 56.

29.       Let the second number be x. Then, first number = 2X and third number = 2x / 3.

2x + x + 2X / 3 = 264     11 x / 3 = 264          X = (264 x 3 / 11) = 72.

30.       Let the numbers be X and (22 – x). Then, 5X = 6(22 – X)    11x = 132      X = 12.

So, the numbers are 12 and 10.