Answer:
+$45
Explanation:
if his actual pay for the week was $100 then from the question he incorrectly calculated it as {$100 + $45} = $145 which is $45 above his actual pay.
Error = measured value - actual
value.
= $145 -$100 =$45.
NOTE: since the value he assumed{$145} is greater than his actual pay{$100}, we have to include a positive sign to the error{$45}.
Therefore, Error = +$45.