EXERCISE 7A (OBJECTIVE TYPE QUESTIONS IN 51 55 SOLUTION )

51.       The sum of three consecutive numbers is 87. The greatest among these three numbers is:

a)      26

b)      28

c)       29

d)      30

52.       The times the first of three consecutive odintegers is 3 more than twice the third. The third integer is:

a)      9

b)      11

c)       13

d)      15

53.       The sum of for consecutive even integers is 1284. The greatest of them is:

A)     320

B)      322

C)      324

D)     326

54.       The sum of three consecutive odd numbers is 20 more than the first of these numbers. What is the middle number?

a)      7

b)      9

c)       11

d)      Data inadequate

e)      None of these

55.       The product of three consecutive even numbers when divided by 8 is 720. The product of their square roots is:

a)      12 10

b)      24 10

c)       120

d)      None of these

ANSWERS 

51.D

52.D

53.C

54.B

55.B

SOLUTION 

51.       Let the numbers be x, x + 1 and X + 2.

Then, x + (x +1) + (x + 2) = 87    3x = 84    X = 28.

Greatest number = (X + 2)= 30.

52.       Let the three integers be x, X + 2 and x + 4, then, 3x = 2 (X + 4) + 3  X = 11.

Third integer = X + 4 = 15.

53.       Let the four integers be x, X + 2,  + 4 and x + 6.

Then, x + (X+ 2) + (X + 4) + (X + 6) = 1284    4x = 1272     X = 318.

Greatest integer = x + 6 = 324.

54.       Let the numbers be x, X + 2 and x + 4.

Then, X + (X + 2) + (x + 4) = X + 20 2 X = 14 X = 7.

Middle number = x + 2 = 9.

55.       Let the numbers be x, X + 2 and x + 4.

Then, X ( X + 2) ( x + 4) / 8 = 720   x(X +2) ( X + 4) = 57 60.

X   ( x + 2) x ( X + 4) = (x (X + 2) ( X + 4) = 5760 = 24 10.