Practice test question

[p_gorsky]

Joan, Kylie, Lillian, and Miriam all celebrate their birthdays today. Joan is 2 years younger than Kylie, Kylie is 3 years older than Lillian, and Miriam is one year older than Joan. Which of the following could be the combined age of all four people today?
51
52
53
54
55

[tommywallach]

Hey Gorsky,

For this question, you need to describe all 4 people in terms of just one of them.


Joan is 2 years younger than Kylie.

So let's say that:

Joan: J
Kylie = J + 2

Kylie is 3 years older than Lillian.

Lillian = J - 1 (because this is 3 less than Kylie)

Miriam is one year older than Joan.

Mirian = J + 1

So now we can add them all up:

J + J + 2 + J - 1 + J + 1 = 4J + 2

So the correct answer needs to be a multiple of 4, plus 2.

51 - odd, no good
52 - multiple of 4, no good
53 - odd, no good
54 - It's a multiple of 4 (52) + 2. Perfect!
55 - odd, no good

Hope that helps!

-t

[p_gorsky]

Gottttt it..thanks!

[tommywallach]

Glad to help!

-t