# some help pwease (1 Viewer)

#### humptydumpty5

##### Member
I need some help with these questions keep getting them wrong and idek why

Rex’s heart pumps 90 mL/beat when resting. His resting pulse is 78 beats per minute. How many litres of blood does his heart pump in an hour?

and

The total cost of electricity for the period 15 March – 17 June (inclusive) is \$387.20. Calculate the average daily cost

#### icycledough

##### Well-Known Member
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.

#### humptydumpty5

##### Member
Thank you so much I appreciate your help means alot thank you

#### icycledough

##### Well-Known Member
Thank you so much I appreciate your help means alot thank you
No worries