SOLUTION: A money box contained some money at first. A took 1/2 the amount of money and another $1500 from the box. After that, B took 1/4 of the remaining amount of money and another $850 f

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: A money box contained some money at first. A took 1/2 the amount of money and another $1500 from the box. After that, B took 1/4 of the remaining amount of money and another $850 f      Log On


   



Question 1207243: A money box contained some money at first. A took 1/2 the amount of money and another $1500 from the box. After that, B took 1/4 of the remaining amount of money and another $850 from the box. In the end, C took the rest of the money left in the box. Given that C took $1400, find the amount of money in the box at first.
Found 4 solutions by josgarithmetic, ikleyn, greenestamps, MathTherapy:
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
p-p%2F2-1500
p%2F2-1500
-
%28p%2F2-1500%29-%281%2F4%29%28p%2F2-1500%29-850
p%2F2-1500-p%2F8-375-850-----------MISTAKE IN SIGN OR OPERATION-- -----

-------THE REST OF THIS IS WRONG---------------
p%2F2-p%2F8-1225
4p%2F8-p%2F8-1225
3p%2F8-1225
-
3p%2F8-1225=1400
3p%2F8=2625
p=%288%2F3%292625
cross%28p=7000%29

Answer by ikleyn(52814) About Me  (Show Source):
You can put this solution on YOUR website!
.


        The  "solution",  calculation and the answer  p=7000  in the post by @josgarithmetic all are incorrect.

        I came to bring a correct solution,  which is below.


p-p%2F2-1500
p%2F2-1500
-
%28p%2F2-1500%29-%281%2F4%29%28p%2F2-1500%29-850
p%2F2-1500-p%2F8%2B375-850
p%2F2-p%2F8-1975
4p%2F8-p%2F8-1975
3p%2F8-1975
-
3p%2F8-1975=1400
3p%2F8=3375
p=%288%2F3%293375
highlight%28p=9000%29


Answer by greenestamps(13203) About Me  (Show Source):
You can put this solution on YOUR website!


This kind of problem is often solved more easily by working backwards, as described below.

C got $1400.

Just before that, B took $850; so before B took $850 the amount was $1400+$850 = $2250.

Just before that, B took 1/4 of the money; that means the $2250 was 3/4 of the money that there was before. So the amount of money before B took 1/4 of it was $2250*(4/3) = $3000.

Just before that, A took $1500; so before A did that the amount was $3000+$1500 = $4500.

And just before that, A took 1/2 of the initial amount; that means the $4500 left after he took 1/2 of the money was also 1/2 of the money. So the initial amount of money was $4500*(2/1) = $9000.

ANSWER: $9000

CHECK:
$9000 minus 1/2 of $9000 = $9000-$4500 = $4500
$4500-$1500 = $3000
$3000 - 1/4 of $3000 = $3000-$750 = $2250
$2250-$850 = $1400


Answer by MathTherapy(10555) About Me  (Show Source):
You can put this solution on YOUR website!
A money box contained some money at first. A took 1/2 the amount of money and another $1500 from the box. After that, B took 1/4 of the remaining amount of money and another $850 from the box. In the end, C took the rest of the money left in the box. Given that C took $1400, find the amount of money in the box at first.

Let original amount be M
After A took matrix%281%2C3%2C+%281%2F2%29M%2C+or%2C+%28M%2F2%29%29 and another $1,500, amount remaining = matrix%281%2C3%2C+%281%2F2%29M+-+%221%2C500%22%2C+or%2C+M%2F2+-+%221%2C500%22%29
After B took matrix%281%2C3%2C+%281%2F4%29%28M%2F2+-+%221%2C500%22%29%2C+%22=%22%2C+M%2F8+-+375%29%29 and another $850, amount remaining = 
Now, with C taking the rest of the money - which happens to be $1,400 - we EQUATE the
2 remainders to get: 
                             3M = 8(3,375) ----- Cross-multiplying
         Original amount, or