How does this work? like i don’t get the topic at all, if you know the answers show how it’s done.

You decide instead to take the train there. the train will take 135 minutes. convert this into hours and minutes.

The average human heart beats 1.15 \cdot 10^51.15⋅10 5 1, point, 15, dot, 10, start superscript, 5, end superscript times per day. there are 3.65 \cdot 10^23.65⋅10 2 3, point, 65, dot, 10, start superscript, 2, end superscript days in one year.how many times does the heart beat in one year? write your answer in scientific notation, and round to one decimal place.

The price of an item has been reduced by 30%. the original price was $30. what is the price of the item now ?