A distant galaxy cluster at a distance of 120 Mpc120\text{ Mpc}120 Mpc is observed to have a recession velocity of 8200 km s-1.
Which expression gives the correct estimate for the age of the universe in seconds?
(Take 1 pc≈3.1×1016 m1\text{ pc} \approx 3.1 \times 10^{16}\text{ m}1 pc≈3.1×1016 m and 1 ly≈9.5×1015 m1\text{ ly} \approx 9.5 \times 10^{15}\text{ m}1 ly≈9.5×1015 m)
age=120×106×9.5×10158200×103\text{age} = \frac{120 \times 10^6 \times 9.5 \times 10^{15}}{8200 \times 10^3}age=8200×103120×106×9.5×1015
age=120×106×3.1×10168200\text{age} = \frac{120 \times 10^6 \times 3.1 \times 10^{16}}{8200}age=8200120×106×3.1×1016
age=120×106×3.1×10168200×103\text{age} = \frac{120 \times 10^6 \times 3.1 \times 10^{16}}{8200 \times 10^3}age=8200×103120×106×3.1×1016
age=120×3.1×10168200×103\text{age} = \frac{120 \times 3.1 \times 10^{16}}{8200 \times 10^3}age=8200×103120×3.1×1016
