Answer: 59
Using the number of years that have passed
|
Julie |
Megan |
Zoey |
today |
32 |
4 |
1 |
in $n$ years |
32 + $n$ |
4 + $n$ |
1 + $n$ |
32 + $n$ = 4 + $n$ + 1 + $n$
= 5 + 2$n$
27 = $n$
In 27 years Julie will be 32 + 27 = 59
Using algebra and Julie's age
Julie's age is $J$
$32-4=28$ so Megan's age is $J-28$
$32-1=31$ so Zoey's age is $J-31$
$$\begin{align}(J-28)+(J-31)&=J\\
\Rightarrow 2J-59&=J\\
\Rightarrow J&=59\end{align}$$ So Julie will be $59$.
Using trial
Julie |
Megan |
Zoey |
M + Z |
|
32 |
4 |
1 |
|
|
42 |
14 |
11 |
25 |
too small |
52 |
24 |
21 |
45 |
too small |
62 |
34 |
31 |
65 |
too big |
61 |
33 |
30 |
63 |
too big |
59 |
31 |
28 |
59 |
perfect |
Julie is 59