assume the yearly cash flows from a $$50,000,2$ year investment are $$30,000$ at the end of year $1$ and $$40,000$ at the end of year $2,$ and the discount rate is $10\%.$ The discount rate equals the IRR when which of the following equations hold true?

$1.30,000/(1+$r$)^1+40,000/(1+$r$)^2=0$

$2.30,000/(1+$r$)^1+40,000/(1+$r$)^2=0\mathrm{.}10$

$3.70,000/(1+$r$)^2=0$

$4.30,000/(1+$r$)^1+40,000/(1+$r$)^2-50,000=0$