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:

0.1039
0.2078
1.1039
2.1039
Answer: Option
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
10
13
14
15
Answer: Option
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:
57
67
77
87
Answer: Option
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

5
2
4

35

Answer: Option
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
5.59
7.826
8.944
10.062
Answer: Option
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