Question 851225
The fuel price is also important.  No prediction possible without it.  
Let p = price per gallon of fuel.


Let y = the number of years owned for both cars.


HYBRID

Cost:  {{{30000+15000(1/50)py}}}
{{{30000+(1500/5)py}}}
{{{30000+300py}}}


REGULAR TYPE

Cost: {{{20000+15000(1/20)py}}}
{{{20000+750py}}}


WHEN ARE COSTS EQUAL?
{{{30000+300py=20000+750py}}}
{{{10000=450py}}}
{{{y=10000/(450p)}}}
{{{highlight(y=25/p)}}}


Choose the fuel price that is needed or as given.  Obviously, the higher the fuel price, the fewer the number of PREDICTED years until the cost for the hybrid reaches as low as the regular car.  Price of fuel is not constant nor steady.  


Some places now are where gasoline is 4 dollars per gallon.
{{{y=25/p=25/4=highlight_green(6&1/4)}}} years