(25)7.5 x (5)2.5 ÷ (125)1.5 = 5?

Question: (25)7.5 x (5)2.5 ÷ (125)1.5 = 5?
[A].

8.5

[B].

13

[C].

16

[D].

17.5

Answer: Option B

Explanation:

Let (25)7.5 x (5)2.5 ÷ (125)1.5 = 5x.

Then, (52)7.5 x (5)2.5 = 5x
(53)1.5
5(2 x 7.5) x 52.5 = 5x
5(3 x 1.5)
515 x 52.5 = 5x
54.5

5x = 5(15 + 2.5 – 4.5)

5x = 513

x = 13.

(0.04)-1.5 = ?

Question:
(0.04)-1.5 = ?

[A].

25

[B].

125

[C].

250

[D].

625

Answer: Option B

Explanation:

(0.04)-1.5 = 4 -1.5
100
   = 1 -(3/2)
25

   = (25)(3/2)

   = (52)(3/2)

   = (5)2 x (3/2)

   = 53

   = 125.

(256)0.16 x (256)0.09 = ?

Question:
(256)0.16 x (256)0.09 = ?

[A].

4

[B].

16

[C].

64

[D].

256.25

Answer: Option A

Explanation:

(256)0.16 x (256)0.09 = (256)(0.16 + 0.09)

   = (256)0.25

   = (256)(25/100)

   = (256)(1/4)

   = (44)(1/4)

   = 44(1/4)

   = 41

   = 4

Which is better investment: 11% stock at 143  or  9% stock at 117?

Question:
Which is better investment: 11% stock at 143  or  9% stock at 117?

[A].

11% stock at 143

[B].

9 3 % stock at 117
4

[C].

Both are equally good

[D].

Cannot be compared, as the total amount of investment is not given.

Answer: Option B

Explanation:

Let investment in each case be Rs. (143 x 117).

Income in 1st case = Rs. 11 x 143 x 117 = Rs. 1287.
143
Income in 2nd case = Rs. 39 x 143 x 117 = Rs. 1394.25
4 x 117
Clearly, 9 3 % stock at 117 is better.
4