It's in expanded form, so you add each part (thousands, hundreds, tens, and ones) separately. the hundreds is missing. looking at the number, it is 900.
Account balance is not proportional to the number of weeks.
It would be .75x=25-13
So .75x=12
x=16 because .75×16=12
Answer:2
2/1=2
I hope this is good enough:
