Let Y = 0.15 / (0.5 / 15)
= (15/100) / [(5/100) / 15)
= 4.5

Correct Option: A

Let Y = 0.15 / (0.5 / 15)
= (15/100) / [(5/100) / 15)
= 4.5

Let (17.28 / y) / (3.6 x 0.2) = 200
Then,17.28 / y = 200 x 3.6 x 0.2
∴ y = 17.28 / (200 x 3.6 x 0.2)
= 1728 / 200 x 36 x 2

Correct Option: D

Let (17.28 / y) / (3.6 x 0.2) = 200
Then,17.28 / y = 200 x 3.6 x 0.2
∴ y = 17.28 / (200 x 3.6 x 0.2)
= 1728 / 200 x 36 x 2
= 0.12.

Let 3420 / 19 = (y / 0.01) x 7
Then , y = ( 3420 / 19) x (0.01 / 7)
= 180 / 700

Correct Option: D

Let 3420 / 19 = (y / 0.01) x 7
Then , y = ( 3420 / 19) x (0.01 / 7)
= 180 / 700
= 9/35

Given expression = 8.32 x 0.999
= 8.32 x (1- 0.001)
= 8.32 - 8.32 x 0.001

Correct Option: C

Given expression = 8.32 x 0.999
= 8.32 x (1-0.001)
= 8.32 - 8.32 x 0.001
=8.32 - .00832
= 8.31168.

Given expression = a² -2ab + b² Where a =9.75 and b=5.75
= (a-b)²
= (9.75 - 5.75)²
= 4²

Correct Option: D

Given expression = a² -2ab + b² Where a =9.75 and b=5.75
= (a-b)²
= (9.75 - 5.75)²
= 4²
=16