1. **Problem Statement:** Marko buys a cellphone with installment payments of 3287.61 every beginning of the month for 4 years, with 5% interest compounded bimonthly. We need to find the cash price (present value) of the cellphone. 2. **Given:** - Payment per period, $R = 3287.61$ - Interest rate per year, nominal compounded bimonthly, $i^{(6)} = 5\% = 0.05$ - Number of years, $t = 4$ - Payments are monthly, so number of payments, $n = 4 \times 12 = 48$ 3. **Find the effective interest rate per month:** Since interest is compounded bimonthly (every 2 months), the nominal rate per bimonthly period is $\frac{0.05}{6} = 0.008333333$ (because 6 bimonthly periods in a year). The effective monthly interest rate $i$ satisfies: $$ (1+i)^2 = 1 + 0.008333333 $$ So, $$ i = \sqrt{1.008333333} - 1 = 0.004158883 $$ Rounded to 6 decimal places, $i = 0.004159$ 4. **Since payments are at the beginning of each month, this is an annuity due.** 5. **Formula for present value of an annuity due:** $$ PV = R \times \frac{1 - (1+i)^{-n}}{i} \times (1+i) $$ 6. **Calculate:** $$ PV = 3287.61 \times \frac{1 - (1+0.004159)^{-48}}{0.004159} \times (1+0.004159) $$ Calculate $(1+0.004159)^{-48}$: $$ (1.004159)^{-48} = \frac{1}{(1.004159)^{48}} \approx \frac{1}{1.221392} = 0.8185 $$ Then, $$ \frac{1 - 0.8185}{0.004159} = \frac{0.1815}{0.004159} = 43.63 $$ Finally, $$ PV = 3287.61 \times 43.63 \times 1.004159 = 3287.61 \times 43.81 = 144,034.68 $$ 7. **Answer:** The cash price of the cellphone is **144034.68** (rounded to nearest hundredths).