Good Evening,
To find this out, turn the percent in to a decimal:
75% ----> .75 )(Divide by 100)
Then multiply the number by the percent decimal:
.024 x .75 = .018
Then subtract the new amount from the original:
.024 - .018 = .006
So the medical device is now emitting a minimum wavelength of .006 nm.
Hope this helps!