Multiple choice

The age of a father is twice that of the elder son. Ten years hence the age of the father will be three times that of the younger son. If the difference of ages of the two sons is $15$ years, the age of the father is

  1. $100$ years
  2. $70$ years
  3. $60$ years
  4. $50$ years
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

F=2E. E-Y=15 => Y=E-15. (F+10)=3(Y+10). 2E+10 = 3(E-15+10) = 3(E-5) = 3E-15. E=25. F=2E=50.

AI explanation

Let the present age of the father be F. Since the father is twice as old as the elder son, the elder son's present age is F divided by 2. The difference between the two sons is 15 years, making the younger son's present age F divided by 2 minus 15. In 10 years, the father will be F plus 10, which equals three times the younger son's age, giving the equation F plus 10 equals 3 times F divided by 2 minus 5. Solving this equation yields F equals 50, so the father is 50 years old.

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