Every month jane plans to add $1 to her account.
Arthur plans to add $3 to his account every month.
If they each start with $10, when will Arthur have three times as much as Jane ?
2007-07-12 11:01:22 · 12 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
Let x be the number of months.
Jane: Amount = 10 + 1x = 10 + x
Arthur: Amount = 10 + 3x
10 + 3x = 3(10 + x)
10 + 3x = 30 + 3x
Not possible.
2007-07-12 11:08:44 · answer #1 · answered by Kemmy 6 · 0⤊ 0⤋
You've already gotten the correct answer mathematically: It will never happen.
Here's a English explanation as well. Arthur adds 3 times as much to his account as Jane does every month. If they started with a balance of zero, Arthur would have 3 times as much money as Jane every month.
Given the above, I could reduce your problem, just by reading it, to: "When will $10 equal $30?" Of course, never.
2007-07-12 18:22:24 · answer #2 · answered by HeadScratcher98 3 · 0⤊ 0⤋
So, the thing to do is to come up with some equations that accurately model the information that is given to you. Once you do this, all you need to do is solve the equations. The first part is the hardest though.
Jane = J
Arthur = A
Account_J = 1 * (# of months) + 10
Account_A = 3 * (# of months) + 10
Account_A = 3 * (Account_J)
Now, substitute the first 2 equations into the third and solve for the number of months.
3*(# months) + 10 = 3*[1*(# months) + 10]
2007-07-12 18:11:24 · answer #3 · answered by CivEng 1 · 0⤊ 0⤋
10 + 3x = 3(10 + x)
10 + 3x = 30 + 3x
The 3x's cancel, setting 10 equal to 30, however we know 10 is not equal to 30. So (unless there is interest you failed to mention), Arthur will never have 3 times as much money as Jane.
2007-07-12 18:10:31 · answer #4 · answered by Anonymous · 0⤊ 0⤋
After x months
J = 10 + x
A = 10 + 3x
10 + 3x = 3*(10+x)
10 + 3x = 30 + 3x
This means it will never happen.
2007-07-12 18:06:23 · answer #5 · answered by Dr D 7 · 0⤊ 0⤋
3 months later but it will be almost 3 times as big as jane's account.
2007-07-12 23:17:21 · answer #6 · answered by Anonymous · 0⤊ 0⤋
A = 3x+10
J = x+10
A/J = (3x+10)/(x+10)
= (3+10/x)/(1 +10/x)
It is easily seen that as x --> infinity, A/J -->3
Thus A/J can never be 3
2007-07-12 19:23:08 · answer #7 · answered by ironduke8159 7 · 0⤊ 0⤋
The answer is at 'infinity'...
If you try to solve this you get 20 = 0 which is obviously not a solution. Therefore you have an infinity somewhere.
2007-07-12 18:21:37 · answer #8 · answered by wilkes_in_london 3 · 0⤊ 0⤋
Is this your homework or something?
the answer is infinite or never in their lifetime.
it will be closer to three times as time approach infinity.
2007-07-12 18:11:39 · answer #9 · answered by Really not_true 5 · 0⤊ 0⤋
10+3mon.=3(10+1mon.),
30-10 =3mon-3mon=o !.never.
2007-07-12 18:12:09 · answer #10 · answered by nasser a 2 · 0⤊ 0⤋