Question

Question A carpenter took the following measurements: 3.4 m, 10.25 m, 20.2 m, and 19 m. How many significant digits does the sum of the measurements have? A: 1B: 2C: 3D:4

Answer 1

We have a set of measurements:

3.4 m, 10.25 m, 20.2 m, and 19 m

Each measurement has its own number of significant digits. For example 3.4 has two significant digits

20.2 has three and 10.25 has four

We are asked how many significant digits does the SUM of them have.

We cannot think of them as isolated measurements, but as a unique result

3.4 + 10.25 + 20.2 + 19 = 52.85

Note the final result has four significant digits, i.e., the numbers 5, 2, 8, and 5

This is our answer: D:4