Calculating the Equivalent Resistance
To calculate the equivalent resistance when the two resistors are connected in parallel, we use the formula:

1/R = 1/R1 + 1/R2

Where R is the equivalent resistance and R1 and R2 are the values of the two resistors.

Substituting the values, we get:

1/R = 1/(5.0 - 0.2) + 1/(10.0 - 0.1)
1/R = 0.199 + 0.099
1/R = 0.298
R = 3.36 kOhm

Therefore, the equivalent resistance is 3.36 kOhm.

Calculating the % Error
To calculate the % error in equivalent resistance, we use the formula:

% Error = (|Measured Value - True Value| / True Value) x 100%

Where Measured Value is the calculated equivalent resistance and True Value is the actual value of the equivalent resistance.

Substituting the values, we get:

% Error = (|3.36 - 3.33| / 3.33) x 100%
% Error = 0.90%

Therefore, the % error in equivalent resistance is 0.90%.

Explanation
When two resistors are connected in parallel, their equivalent resistance is smaller than either of the individual resistances. This is because the total current in the circuit is divided between the two resistors, resulting in a lower overall resistance.

The % error in equivalent resistance is a measure of how close the calculated value is to the true value. In this case, the % error is very small, indicating that the calculated value is very close to the true value.

It is important to note that the % error in equivalent resistance can be influenced by a variety of factors, including the accuracy of the resistors, the precision of the measuring instruments, and the skill of the operator. Therefore, it is important to use high-quality components and equipment and to follow proper measurement techniques to minimize errors.