Question 990521
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F=father's age; S=son's age
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(F+S)/2=54yrs
F+S=108yrs
S=108yrs-F
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F+10yrs=3(S+10yrs)
F+10yrs=3(108yrs-F+10yrs)
F+10yrs=3(118yrs-F)
F+10yrs=354yrs-3F
4F=344yrs
F=86yrs
ANSWER: Father's present age is (c) 86 years.
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CHECK:
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S=108yrs-86yrs=22yrs
Son's age is 22 years.
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F+10yrs=3(S+10yrs)
86yrs+10yrs=3(22yrs+10yrs)
96yrs=3(32yrs)
96yrs=96yrs