Juan is 8 years older than his sister. In 3 years, he will be twice as old as she was then how old are thy now?
2007-03-08 13:38:50 · 6 answers · asked by HITCH 2 in Science & Mathematics ➔ Mathematics
5 and 13
2007-03-08 13:42:30 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Here's an example of how to do it. The expressing of story problems is like learning a language: you HAVE to do it to learn it. There is no other way. So, practice.
J = S+8 <= be sure that the + 8 is added to the correct person
J+3 = 2x (S+3) <= this is a little fuzzy since "she was then" is not well phrased or clear English. It is incorrectly worded: it should either be "she is now" or "she will be then"
Expanding the last equation: J+3 = 2S+6
or J=2S+3
then equating to the first equation
J=S+8 = 2S+3 or S+5 = 2S so 5=S
and so J=S+8 = 13
to check 13+3 = 2(5+3) or 16 = 16 check!
2007-03-08 21:53:12 · answer #2 · answered by Anonymous · 0⤊ 0⤋
J=S+8. 2S=J+3. 2S-3=S+8. S=11. His sister is 11 and Juan is 19.
2007-03-08 21:50:27 · answer #3 · answered by misoma5 7 · 0⤊ 0⤋
Juan 13
Sister 5
2007-03-08 21:51:32 · answer #4 · answered by CJ E 2 · 0⤊ 0⤋
x - Juan
y- Sister
8 + y = x
x + 3 = 2(y+3)
2007-03-08 21:44:50 · answer #5 · answered by Anonymous · 0⤊ 0⤋
try 11 and 19.
2007-03-08 21:45:53 · answer #6 · answered by Deni 1 · 0⤊ 0⤋