Investing over time

If you would like to accumulate $1,000,000 over 15 years, at 7% per year, you will have to invest $3214.35 per month:

np.pmt(rate=((1+0.07)**(1/12) - 1), 
       nper=15*12, pv=0, fv=1000000)

But what if you were willing to wait an extra 15 years, for a total of 30 years? How much will you need to invest each month?

Roughly the same amount as before.

Half the original amount.

Less than half the original amount.

Exercise