42 mph to km per hour conversion result above is displayed in three different forms: as a decimal (which could be rounded), in scientific notation (scientific form, standard index form or standard form in the United Kingdom) and as a fraction (exact result). Every display form has its own advantages and in different situations particular form is more convenient than another. For example usage of scientific notation when working with big numbers is recommended due to easier reading and comprehension. Usage of fractions is recommended when more precision is needed.
If we want to calculate how many Kilometers per Hour are 42 Miles per Hour we have to multiply 42 by 25146 and divide the product by 15625. So for 42 we have: (42 × 25146) ÷ 15625 = 1056132 ÷ 15625 = 67.592448 Kilometers per Hour
So finally 42 mph = 67.592448 km per hour
