While the solution is done on monthly basis i.e. PMT = 72,000/12 and n = 12 * 10 years

I missed the “in equal monthly installments” and focussed on 72,000 per year saving, so did the return calculation on yearly basis, i.e. PMT = 72,000 and n=12 years.

And arrived at 8.29% (vs. solution 8.09%).

Is this a complete 0 credit for me, or there is some partial credits here? Appreciate the feedback!!