Answer:
31 payments
Step-by-step explanation:
the present value of the first annuity is:
$1,200 / (1 + 1%)⁸ + $1,200 / (1 + 1%)¹⁶ + $1,200 / (1 + 1%)²⁴ + $1,200 / (1 + 1%)³² + $1,200 / (1 + 1%)⁴⁰ = $1,108.18 + $1,023.39 + $945.08 + $872.76 + $805.98 = $4,755.39
to determine the length of the second annuity:
PV = annuity payment x annuity factor
annuity factor = PV / annuity payment = $4,755.39 / $180 = 26.4188333
using an annuity table we must look for a present value annuity factor that corresponds to 1% interest rate and is close to 26.4188333
the annuity factor is between 30 and 31 payments. Since the final payment has to be less or equal to $180, we have to choose 31 payments.