
By: chino (offline) Wednesday, August 17 2011 @ 08:17 AM CDT (Read 1205 times)



chino 
Mary and Andy have some money left in their cash card.
If Mary spends $2 each day and Andy spends $3 each day, Mary would have $24 left after Andy had finished using all his money.
If Andy spends $2 each day and Mary spends $3 each day, Andy would have $29 left after Mary had finished spending all her money.
Find the money each of them have in their cash card.
need to see the steps how to solve such question.
thanks

Newbie
Registered: 03/14/10 Posts: 14





By: pkrdd (offline) Wednesday, August 17 2011 @ 10:57 PM CDT



pkrdd 
suppose the number of days they spent in both cases as A & B
If MARY = $2, Andy = $3 per day,
total together = $5 * A (number of days) + 24
If MARY = $3, Andy = $2 per day,
total together = $5 * B (number of days) + 29
Their total remains same in both cases
ie 5A + 24 = 5B + 29
> A = B+1
Mary total when she spends $2 per day and 3$ per day is same
2A + 24 = 3B
Substituting for A
2B + 2+ 24 = 3B
B= 26, A=27
Mary = 2 *27 +24 = 78
Andy = 3 *27 = 81
Hope it helps

Junior
Registered: 01/11/10 Posts: 16





By: chino (offline) Saturday, August 20 2011 @ 08:32 PM CDT



chino 
not sure how your equation
5A + 24 = 5B +29 end up
A = B + 1 ???
can help explain this, thank you.

Newbie
Registered: 03/14/10 Posts: 14





By: pkrdd (offline) Sunday, August 21 2011 @ 02:22 AM CDT



pkrdd 
If you draw model with A as 5 units + 25 and B as 5 units + 29
Then you can easily derive 5A = 5B + 5 (Difference of 29 & 25)
alternately, if you do mathematically also
5A + 24 =5B + 29
> 5A = 5B + (29 24)
>5A =5B + 5
> A= B + 1

Junior
Registered: 01/11/10 Posts: 16



