As you used two diferent instruments, one is more sensitive than the other.
Explanation:
The sensitivity of an instrument is the minimum amount of magnitude that can be differentiate a measurement system.
In method A, you got 27 cm, so if in method B, you got 27.00, method B is more sensitive. It's like saying that one system measures more than the other
U-238 The number besides the U means its total molar mass. The molar mass of this element is 238 Molar mass= protons + neutrons This means that 238= 146 + protons Do 238 - 146 Answer is 92
