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# Rita is 12 years old and her father is 39 years old. In how many years will Rita be twice as young as her father?

Rita is 12 years old and her father is 39 years old. In how many years will Rita be twice as young as her father?

### 3 Answers by Expert Tutors

Parviz F. | Mathematics professor at Community CollegesMathematics professor at Community Colle...
4.8 4.8 (4 lesson ratings) (4)
1
2(12 + n )= (39 + n)   (1)

24 + 2n = 39 +n

n = 39 -24 = 15

After 15 years Rita 's age = 12 + 15 = 27, father age = 39 +15 = 54

54 = 2 ( 27).

Notice that whole word problem was put into one algebraic statement of equation (1).

Jim S. | Physics (and math) are fun, reallyPhysics (and math) are fun, really
4.7 4.7 (184 lesson ratings) (184)
1
Moshe,
Another less intuitive way to do this problemâ€¦.

Let Af=t+39, the fathers age, t is time in years (t=0 now)and Ad=t+12, the daughters age then we want to calculate at what time will Ad=Af/2 so we must have t+12=(t+39)/2, solving this equation for t gives t=15 years. In 15 years Rita will be 15+12 or 27 years old and her father will be (15+39)/2 =54 years old.

Jim
Stephen W. | Othello, Eltopia, Connell, Pasco, West Pasco - I am in your area!Othello, Eltopia, Connell, Pasco, West P...
4.9 4.9 (43 lesson ratings) (43)
1
Subtract the two ages:

39 - 12 = 27

Rita will be half as old (twice as young) as her father when she is 27 - or in 15 years.