.
From the condition, you have
= . (1)
Multiply both sides by 3*5 = 15. You will get
6A = 10B, or
3A = 5B. (2)
You have also second equation
A + B = 4800. (3)
Multiply its both sides by 3. You will get
3A + 3B = 3*4800 = 14400.
In the left side, replace 3A by 5B, based on equation (2). You will get
5B + 3B = 14400, or
8B = 14400,
B = 14400/8 = 1800.
So, the amount B is just found: it is 1800 dollars.
The last step is to find A. For it, subtract 1800 from 4800
A = 4800 - 1800 = 3000 dollars.
ANSWER. A has $3000; B has $1800.
-------------
comment from student: Why did you multiply equation (3) by 3 ?
-------------
My response : Good question, thanks for asking.
I multiply equation (3) by 3 in order for to have this term " 3A ", which I later replace by " 5B ".
My secret goal is to get an equation for one unknown " B " only, and for it I make all these transformations.
Is everything clear to you now ?
If you still have questions, do not hesitate to post them to me . . .
Have a nice day (!)
-------------
comment from student: How did you get 3A = 5B from 6A = 10B ?
-------------
My response : I divided both sides of the equation 6A = 10B by 2.