SOLUTION: Liza is one year older than her sister. In four years Liza will be three times older than she is now. How old is Liza's sister now?

Question 1151259: Liza is one year older than her sister. In four years Liza will be three times older than she is now. How old is Liza's sister now?

Found 3 solutions by josgarithmetic, ikleyn, MathTherapy:
Answer by josgarithmetic(39618)   (Show Source): You can put this solution on YOUR website!
Liza x+1
Sister x

In four years:

Solve for x.

---

"..., three times older than she is now."

.
.
Answer by ikleyn(52793)   (Show Source): You can put this solution on YOUR website!
.

The original formulation in the post is DEFECTIVE, INACCURATE and potentially DANGEROUS.

The correct, accurate and safe formulation is THIS :

Liza is one year older than her sister. In four years Liza will be three times as old as she is now. How old is Liza's sister now?

Solution

Let x be the Lisa's age now. Then from the condition x + 4 = 3x. (In four years Liza will be three times as old as she is now). From the equation, 4 = 3x - x 4 = 2x x = 4/2 = 2. So, Lisa is 2 years old now. ANSWER. Lisa' sister is 2-1 = 1 year old now.

Solved.

-------------------

Here I want to explain you, why the original formulation in the post is DEFECTIVE, INACCURATE and potentially DANGEROUS.

In English, in distinction from many other languages, the statement

In four years Liza will be three times older than she is now.

means "In four years Liza will be FOUR times as old as she is now."

In English, it is the only possible interpretation --- and there is NO any other interpretation.

But it is, certainly and definitely, not that meaning the author of the problem was going to implement.

Probably, the author of the problem is/was not familiar with this norm/form of English --- so, learn it from my post.

The second message from me is that the "solution" and the setup in the post by @josgarithmetic is WRONG.

So, you better IGNORE his post for your safety.

Answer by MathTherapy(10552)   (Show Source): You can put this solution on YOUR website!

If this were meant as @IKLEYN indicated then Liza's sister is
RELATED QUESTIONS
Liza's age is two more than thrice the age of her younger sister. If her younger sister... (answered by ikleyn)
Liza’s age is four less than thrice the age of her younger sister. If two years ago,... (answered by josgarithmetic,ikleyn)
Liza is now 3 times as old as her brother. Five years ago, the sum of their ages was 18... (answered by josgarithmetic)
Liza is now 3 times as old as her brother. 5 years ago, the sun of their ages was 18... (answered by richwmiller)
10 years ago, mike was four times as old as Liza. Now he is only twice as old as Liza.... (answered by math_helper)
anton is four years older than liza. the product of his age 3 years from now and liza's... (answered by jorel555)
Liza is 25 years younger than her mother. After 4 years, her mother's age will be twice... (answered by advanced_Learner)
ten yrs. ago, mike was four times as old as liza. Now he is only twice as old as Liza.... (answered by math_helper)
Julia is currently 26 years older than her son. In six years, she will be three times... (answered by Alan3354)