Question 889873
M = J + G - 1
J = G + 8
M + J + G = 35
Substitute the value of M from the first equation into the bottom equation
M + J + G = 35
(J+G-1) + J + G = 35
Substitute the value of J above into the new equation
(J+G-1) + J + G = 35
(G+8)+G-1 + (G+8) + G = 35
Add
4G + 15 = 35
Subtract 15 from each side
4G = 20
Divide each side by 4
G = 5
If Gloria is 5, then Jane is 13. [ Jane is eight years older than Gloria]
If Gloria is 5 and Jane is 13, then Mary is 17 [Mary is one year younger than the sum of janes and Gloria's ages]
Add their ages -- 5 + 13 + 17 = 35
Success!