Sue and Fred have a combined age of 42 years. If Sue's age is 1/2 of Fred's, how old is Fred in years?
16
20
23
28
35
2007-09-22 05:23:34 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Sue + Fred = 42
Sue = Fred / 2
Plug the second equation into the first:
Fred / 2 + Fred = 42
Fred + 2Fred = 84
3Fred = 84
Fred = 28
Now that we know Fred we can find Sue:
Sue = 28/2 = 14.
Sue = 14.
Fred = 28.
Check:
14+28 = 42
28 / 2 = 14.
2007-09-22 05:28:57 · answer #1 · answered by John 1 · 0⤊ 0⤋
Sue and Fred have a combined age of 42 years. If Sue's age is 1/2 of Fred's, how old is Fred in years? Fred is 28 years old and Sue is 14.
2007-09-22 12:39:09 · answer #2 · answered by Will 4 · 0⤊ 0⤋
sue's age = S
fred's age = F
S + F = 42
S = (1/2)F
substitute for S
(1/2)F + (1)F = 42
(3/2)F = 42 multiply both sides by 2/3
(2/3)(3/2)F = 42(2/3); F = 42(2/3) = 14(2) = 28
S + 28 = 42
S = 42 - 28 = 14
Look back at the problem to see what they are asking.
Fred is 28
2007-09-22 12:46:44 · answer #3 · answered by trogwolf 3 · 0⤊ 0⤋
Fred = X therefore Sue = 1/2X
X + 1/2X =42 28 + 14 = 42
42 =42
3/2X =42
------ -----
3/2 3/2
X = 28
2007-09-24 13:02:59 · answer #4 · answered by gzlakewood@sbcglobal.net 4 · 0⤊ 0⤋
28
2007-09-22 12:37:53 · answer #5 · answered by Anonymous · 0⤊ 0⤋
Let sue be x yrs. Hence fred is 2x yrs.
Therefore x+2x= 42
3x= 42
x= 14.
Therefore sue is x yrs = 14 yrs.
And fred is 2x yrs= 28 yrs.
2007-09-22 12:35:39 · answer #6 · answered by Nina T 3 · 0⤊ 0⤋