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Amanda is $$7$$ years old last year. In $$2$$ years times, she is double of her sister\textquotesingle s age. What is the sum of their age this year? 
Overseas Competition->Knowledge Point->Word Problem Modules->Age Problems
$$2$$ years time, Amanda $$10$$ and sister $$5$$. Total $$15$$.  This year, $$15-2-2=11$$. 