Weekly Rompecabeza: How Old Are They?

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Dollar Shave Club members are amongst the smartest people in the world. But that doesn’t mean they can’t be smarter. With the help of our friends at American Mensa, DSC is proud to bring you weekly Rompecabezas (Spanish for head breakers) to boost your IQ into the Thermosphere.



Answer:

(Let X and Y represent Alec’s and his grandfather ages, respectively. The two sentences translate into algebra as X = 4Y and 5 (X  – 5) = (Y – 5). Substituting Y = 4X into the second sentence gives 5(X – 5) = (4X – 5). Solving, X = 20 and so Y = 80.)

Alec is 20, and his grandfather is 80.