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Joe is 5 years older than Sally. In 15 years Joe will be 3 times as old as Sally is now. How old is Sally now? Hint: Write Joe's age now in terms of Sally's age now. Then write Joe's age in 15 years using the expression you just wrote for Joe's age now. Then using S for Sally's age now, write the equation in only one variable "S" and solve it.

2006-08-15 06:22:25 · 19 answers · asked by Anonymous in Science & Mathematics Mathematics

19 answers

Let present age of Sally is = x years
Therefore present age of Joe = (x+5)years
After 15 years age of Joe will be = x+5+15=(x+20) years
As per given conditions
(x+20)= 3(x)
20 = 3x -x
20 = 2x
Therefore x = 10
The present age of Sally is =10 years

2006-08-15 06:36:39 · answer #1 · answered by Amar Soni 7 · 0 0

10

2006-08-15 13:38:39 · answer #2 · answered by lkamh 2 · 0 0

J = S+5

3*S = J+15 = (S+5)+15 = S+20
2*S = 20
S = 10

2006-08-15 13:30:23 · answer #3 · answered by Kyrix 6 · 0 0

J -S = 5
J+15 = S * 3

J= S+ 5
S+5 +15 = S*3

= > 2 S= 20
S= 10.

=================== Use this as an example and do your own homework from now on.

2006-08-15 13:29:12 · answer #4 · answered by Anonymous · 0 0

Sally is 10 now.

2006-08-15 13:29:52 · answer #5 · answered by Cary Grant 4 · 0 0

Sally is 10 now.

2006-08-15 13:25:20 · answer #6 · answered by Anonymous · 0 0

Sally is 10.
I was going to prove I'm smart by telling you it's "you're" not "your." Didn't think there was an easy math problem as well.

2006-08-15 13:41:01 · answer #7 · answered by candy2mercy 5 · 0 0

What are u some kind of Math Wizard ? I mean come on ..... Some of ur questions are juss like whoa Math Nerd !!!! Get a life loser !!!

oh yeah sallys 10

2006-08-18 00:13:16 · answer #8 · answered by Anonymous · 0 0

j = s + 5
j + 15 = 3s
j + 15 = 3(j - 5)
30 = 2j
j (present) = 15
s (present) = 10
j (future) = 30

2006-08-15 13:25:29 · answer #9 · answered by shmifty__14 5 · 0 0

J+15=3S
J=S+5
S+20=3S
2S=20
S=10

Sally is 10 years old.

2006-08-15 13:26:59 · answer #10 · answered by knivetsil 2 · 0 0

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