A numerator or a denominator can be a fraction itself, but you don't have to leave it that way. When dividing something by a fraction you multiply by the reciprocal of the fraction, so the ratio of A to B is equal to A x 1/B.
The ratio of 1 mile per (8/5) km can be expressed as 1 mi / (8 km / 5), which equals 1 mi x (5 / 8 km). Performing the multiplication gives you the ratio of 5 mi / 8 km.
This depends on the context. However, it is good practice to reduce a ratio or a fraction to its lowest possible term. The only time you wouldn't simplify a ratio or fraction is if it signified something in its original state.
2/3
I am not sure whether the term "incommensurable" is appropriate here; the official term is "irrational", which means it can't be expressed exactly as a ratio: you can't write a fraction with integer numerator and denominator which is exactlyequal to the square root of 5 (or of any other integer that is not a perfect square) - but you can obviously get very close to the exact value with such a fraction. If you write the square root of 5 as a decimal, you will get an infinite amount of decimal digits, which will not repeat.I am not sure whether the term "incommensurable" is appropriate here; the official term is "irrational", which means it can't be expressed exactly as a ratio: you can't write a fraction with integer numerator and denominator which is exactlyequal to the square root of 5 (or of any other integer that is not a perfect square) - but you can obviously get very close to the exact value with such a fraction. If you write the square root of 5 as a decimal, you will get an infinite amount of decimal digits, which will not repeat.I am not sure whether the term "incommensurable" is appropriate here; the official term is "irrational", which means it can't be expressed exactly as a ratio: you can't write a fraction with integer numerator and denominator which is exactlyequal to the square root of 5 (or of any other integer that is not a perfect square) - but you can obviously get very close to the exact value with such a fraction. If you write the square root of 5 as a decimal, you will get an infinite amount of decimal digits, which will not repeat.I am not sure whether the term "incommensurable" is appropriate here; the official term is "irrational", which means it can't be expressed exactly as a ratio: you can't write a fraction with integer numerator and denominator which is exactlyequal to the square root of 5 (or of any other integer that is not a perfect square) - but you can obviously get very close to the exact value with such a fraction. If you write the square root of 5 as a decimal, you will get an infinite amount of decimal digits, which will not repeat.
10 to 3
99/40
This depends on the context. However, it is good practice to reduce a ratio or a fraction to its lowest possible term. The only time you wouldn't simplify a ratio or fraction is if it signified something in its original state.
It is: 2/3
2/3
I am not sure whether the term "incommensurable" is appropriate here; the official term is "irrational", which means it can't be expressed exactly as a ratio: you can't write a fraction with integer numerator and denominator which is exactlyequal to the square root of 5 (or of any other integer that is not a perfect square) - but you can obviously get very close to the exact value with such a fraction. If you write the square root of 5 as a decimal, you will get an infinite amount of decimal digits, which will not repeat.I am not sure whether the term "incommensurable" is appropriate here; the official term is "irrational", which means it can't be expressed exactly as a ratio: you can't write a fraction with integer numerator and denominator which is exactlyequal to the square root of 5 (or of any other integer that is not a perfect square) - but you can obviously get very close to the exact value with such a fraction. If you write the square root of 5 as a decimal, you will get an infinite amount of decimal digits, which will not repeat.I am not sure whether the term "incommensurable" is appropriate here; the official term is "irrational", which means it can't be expressed exactly as a ratio: you can't write a fraction with integer numerator and denominator which is exactlyequal to the square root of 5 (or of any other integer that is not a perfect square) - but you can obviously get very close to the exact value with such a fraction. If you write the square root of 5 as a decimal, you will get an infinite amount of decimal digits, which will not repeat.I am not sure whether the term "incommensurable" is appropriate here; the official term is "irrational", which means it can't be expressed exactly as a ratio: you can't write a fraction with integer numerator and denominator which is exactlyequal to the square root of 5 (or of any other integer that is not a perfect square) - but you can obviously get very close to the exact value with such a fraction. If you write the square root of 5 as a decimal, you will get an infinite amount of decimal digits, which will not repeat.
10 to 3
4/25
99/40
2yr to 3yr
It is 1 to 2.
The term used is "rational". This means "can be written as a ratio" rather than "logical".
7/100
3/50