please Christoph can you explain what you are doing from y/2=x(1+r) => y=2x+2xr insert in x/y+x => x/(2x+2xr+x) => 1/(3+2r)
In his assumption, x is the money he saved in the first year and y is the money he spent in the first year. So the total money he earned in the first year is x+y
The question says
The money he saved in the last year is what fraction of his total income, in terms of r
Thanks AJB 77 ! great explanation
a small question plz how do you get this y/2=x(1+r)
This means that the fraction needed is x/(x+y)
This has 2 variables. So you solve for y in terms of x and r based on the question and the replace y with that value in the above fraction.
Does this help?