If the altitudes of a star at its upper and lower transits are 60° 30' and 19° 30' respectively, the latitude of the place, is

Answer: Option C

Correct Answer: Option C: 40°

Explanation:

The latitude ($\varphi$) of a place can be determined using the formula:

$$\varphi =\frac{\text{Altitude at Upper Transit}+\text{Altitude at Lower Transit}}{2}$$

Given:

Upper Transit Altitude = 60° 30'

Lower Transit Altitude = 19° 30'

$$\varphi =\frac{(60°30^{\prime })+(19°30^{\prime })}{2}$$

Converting minutes:

$$\varphi =\frac{(60.5+19.5)}{2}=\frac{80}{2}=40°$$

Thus, the latitude of the place is 40°.