1.Your task is twice easier than mine.
2.Your task is two times easier than mine.
The first one seems incorrect to me. Am I right?
"A is twice as hard/heavy/expensive/tall as B" does make sense because it means twice the difficulty/weight/price/height of B.
For example, if B weighs 4kg. and A is two times lighter (ie. 8kg lighter), A weighs -4kg.