So for question one, you want to find the number of beats per hour, then multiply this by the volume per beat. So 78 beats per minute would be 78 * 60 = 4680 beats per hour. Then applying the 90 mL/beat, we know that the volume of blood would be 4680 * 90 = 421,200 mL, or 421.2L of blood in an hour.

For question 2, you would just want to find the days from that period and use the algorithm 387.20 / number of days. Be careful though that the question says 'inclusive', so you would include the beginning and end day. So consider each month individually; March would go from 15th to 31st, so 31 - 15 + 1 = 17 days. April would have 30 days. May would have 31 days. June would have 17 days. Adding these up (17 + 30 + 31 + 17) gets 95 days. Thus, 387.20 / 95 = 4.0757894... = $4.08 (nearest cent) as the average daily cost.