SOLUTION: The sum of the ages of Derek and Andy is 50. In five years time, the age of Andy will be four times the age of Derek now. how old is each boy?

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Question 1106519: The sum of the ages of Derek and Andy is 50. In five years time, the age of Andy will be four times the age of Derek now. how old is each boy?
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52864) About Me  (Show Source):
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.
Mental solution 

    In 5 years the sum of their ages will be 50 + 2*5 = 60.


    So, in 5 years the sum of their ages will be 60 and the age of one will be 4 times the age of the other.


    Now everybody can easily calculate their ages in 5 years in the mind: in 5 years they will be 12 and 48.


    Hence, now Andy is 48-5 = 43 and Andy is 12-5 = 7 years old.



Answer by greenestamps(13206) About Me  (Show Source):
You can put this solution on YOUR website!


The other tutor misread the problem....

Let x be Derek's age; then Andy's age is (50-x).
In 5 years, Derek's age will be (x+5); Andy's will be (55-x).

The problem says Andy's age in 5 years will be 4 times Derek's current age:
55-x+=+4x%29
55+=+5x
11+=+x

Derek's age is x=11; Andy's age is 50-x = 39.