Aptitude - Square Root and Cube Root

Exercise :: Square Root and Cube Root - General Questions

6. 

If a = 0.1039, then the value of 4a2 - 4a + 1 + 3a is:

A. 0.1039
B. 0.2078
C. 1.1039
D. 2.1039

Answer: Option C

Explanation:

4a2 - 4a + 1 + 3a = (1)2 + (2a)2 - 2 x 1 x 2a + 3a

   = (1 - 2a)2 + 3a

   = (1 - 2a) + 3a

   = (1 + a)

   = (1 + 0.1039)

   = 1.1039


7. 

If x = 3 + 1 and y = 3 - 1 , then the value of (x2 + y2) is:
3 - 1 3 + 1

A. 10
B. 13
C. 14
D. 15

Answer: Option C

Explanation:

x = (3 + 1) x (3 + 1) = (3 + 1)2 = 3 + 1 + 23 = 2 + 3.
(3 - 1) (3 + 1) (3 - 1) 2

y = (3 - 1) x (3 - 1) = (3 - 1)2 = 3 + 1 - 23 = 2 - 3.
(3 + 1) (3 - 1) (3 - 1) 2

x2 + y2 = (2 + 3)2 + (2 - 3)2

   = 2(4 + 3)

   = 14


8. 

A group of students decided to collect as many paise from each member of group as is the number of members. If the total collection amounts to Rs. 59.29, the number of the member is the group is:

A. 57
B. 67
C. 77
D. 87

Answer: Option C

Explanation:

Money collected = (59.29 x 100) paise = 5929 paise.

Number of members = 5929 = 77.


9. 

The square root of (7 + 35) (7 - 35) is

A. 5
B. 2
C. 4
D.

35

Answer: Option B

Explanation:

(7 + 35)(7 - 35) = (7)2 - (35)2  = 49 - 45  = 4  = 2.

10. 

If 5 = 2.236, then the value of 5 - 10 + 125 is equal to:
2 5

A. 5.59
B. 7.826
C. 8.944
D. 10.062

Answer: Option B

Explanation:

5 - 10 + 125 = (5)2 - 20 + 25 x 55
2 5 25

= 5 - 20 + 50
25

= 35 x 5
25 5

= 355
10

= 7 x 2.236
2

= 7 x 1.118

= 7.826