Let the youngest sister be n years Lana will be 2n years, as her youngest sister is half her age The age of the twins separately will be 2n-2 as they are 2 years younger than Lana So, the equation looks like this: n + 2n + 2(2n-2) = 45 Now solve for n: 3n + 4n - 4 = 45 7n - 4 = 45 7n = 49 n = 7 So the youngest sister is 7, Lana is 14 and the twins are 12. 14 + 12 + 12 + 7 =45
