A car driver spends 3hrs driving at an average speed of 80km/hr, stops for 30 minutes to have some rest, and then drives at an average speed of 90km/hr for 2 hours.
Calculate the average speed during the whole journey​

The average speed throughout the journey was 76.36 kilometers per hour.

Explanation:

Given that a car driver spends 3hrs driving at an average speed of 80km / hr, stops for 30 minutes to have some rest, and then drives at an average speed of 90km / hr for 2 hours, to determine the average speed during the whole journey the following calculation must be performed:

80 km / h x 3 = 240 km

90 km / h x 2 = 180 km

240 + 180 = 420 km

3 + 2 + 0.5 = 5.5 hours

420 / 5.5 = 76.36

Thus, the average speed throughout the journey was 76.36 kilometers per hour.

specific latent heat of fusion, lf, of a substance is defined as the amount of heat required to change a unit mass of the substance from solid to liquid state, without any change in the temperature.

explanation:

co2reflects heat radiation back to earth buning coal and oil emits co2 globe warms