Select the option that is related to the third number on the same basis as the second number is related to the first number.
2.5 : 0.0025 :: 3.6 : ?
$$\frac{2.5}{1000}\ =\ 0.0025$$
$$\frac{3.6}{1000}\ =\ 0.0036$$
Hence option (a) is the correct answer.
Create a FREE account and get: