Question

Paulo uses an instrument called a densitometer to check that he has the correct ink colour.

Answer 1

If it is said that the range of the answer should be +/- 10% of the particular value, we have to find out the percentage of that particular value. Therefore 10% of 1.8 is,

1.8 * 10/100 = 0.18

If we add this value to the original value,
1.8+0.18 = 1.98

If we subtract this value from the original value,
1.8-0.18 = 1.62

therefore the range will be,
from 1.62 to 1.98