SOLUTION: Rita is 23, and joel is 15. How many years ago was rita 3 times as old joel?

Algebra.Com
Question 1167875: Rita is 23, and joel is 15. How many years ago was rita 3 times as old joel?
Found 2 solutions by ikleyn, greenestamps:
Answer by ikleyn(52794)   (Show Source): You can put this solution on YOUR website!
.

    23 - x = 3*(15-x)

    23 - x = 45 - 3x

    3x - x = 45 - 23

    2x     = 22

     x     = 22/2 = 11.


ANSWER.  11 years ago.

Solved.


Answer by greenestamps(13200)   (Show Source): You can put this solution on YOUR website!


You should know how to set up and solve this problem using formal algebra, as shown by the other tutor.

However, you can get some good brain exercise and good practice in problem solving by solving the problem informally, using logical reasoning and simple arithmetic.

The difference in their ages is, and always will be, 8 years.

Given that age difference, when Rita was 3 times as old as Joel, mental arithmetic tells us Rita was 12 and Joel was 4.

Rita is now 23, so that was 23-12 = 11 years ago.

ANSWER: 11 years
RELATED QUESTIONS

Dorthy is 14 years youngfer than Rita. Ten years ago Rita was 3 times as old as Dorthy... (answered by Maths68)
Joshua is 57 years old. Rita is 29 years old. How many years ago was Joshua's age 3 times (answered by josgarithmetic)
Norman is 2 years older than Rita. In 5 years’ time, Rita will be 4 times as old as... (answered by josgarithmetic,MathTherapy)
Robert is 4/5 as old as Joel. Four years ago, he was 3/4 as old as Joel, how old are... (answered by Edwin McCravy)
Mark is 8 years older than his sister Rita. Four years ago rita was two thirds as old as... (answered by Boreal,greenestamps)
The sum of Jerry and Joel's age is 36. Nine years ago, Jerry was twice as old as Joel.... (answered by amarjeeth123)
Ana is 23, and james is 15. How many years ago was ana 3 times as old as... (answered by ikleyn)
Help me answer this? Jack is twice as old as Jill. Into years Jack will be four times as (answered by josmiceli,MathLover1)
Mary is 2 years older than Ed, and 3 years ago Mary was twice as old as Ed. Find their... (answered by ikleyn)