Question

Lana is the oldest of four sisters. Her youngest sister is half her age. The other two sisters are twins 2 years younger than Lana. When the four sisters' ages are added together, the result is 45. If the youngest sister is n years old, what is n?

Answer 1

It is mostly a translation problem:

"youngest sister is n years old"

Youngest Sister: n

"youngest sister is half her age"

Lana: 2n <== You need to see why this is so.

"twins 2 years younger than Lana"

Twins: 2n - 2 <== You need to see why this is so.

"added together, the result is 45"

n + 2(2n-2) + 2n = 45 <== You need to see why this is so.