Problema Solution
Devon, frank, Morris, & Pedro belong to the same work out gym. The gym rules prohibit the staff from giving out personal information about their clients, however each of the five guys said just enough so you can figure out their exact weights.
Devon: Pedro weighs 18 pounds more then I do. None of us weighs over 200 pounds.
Frank: MY weight is divisible by 7. Morris weighs 121 pounds more than I do.
Fua: 3 people are more then I am. Pedros weight is a prime number
Morris: I'm heavier than Pedro. Devon is the lightest.
Pedro: Morris weight is divisible by ten. the five of us together total exactly 840 pounds.
Answer provided by our tutors
There is a typing mistake in the question, it should say "Morris weighs 12 pounds more than I do." instead of "Morris weighs 121 pounds more than I do."
Devon - 155
Fua - 164
Frank - 168 (divisible by 7)
Pedro - 173 (18 more than Devon, and a prime number)
Morris - 180 (12 more than Frank, and divisible by 10)
Total of 840, all rules met.