Question 1058227

The sum of the ages of three sisters is 78 years. The second sister is eighteen years less than twice the first sister's age. The third sister is eight years older than the first sister. How old are the sisters?
<pre>Let the 1st sister's age be F
Then 2nd sister's age is: 2F - 18
And, the 3rd sister's age = F + 8
Since their ages sum to 78, we get: F + 2F - 18 + F + 8 = 78
4F - 10 = 78
4F = 88
F, or 1st sister's age is: {{{highlight_green(matrix(1,3, 88/4, or, 22))}}}
{{{highlight_green(matrix(2,9, 2^(nd), "sister's", age, "is:", 2(22) - 18, or, 44 - 18, or, 26, 3^(rd), "sister's", age, "is:", 22, "+", 8, or, 30))}}}