# calculating heart rate a level biology

Can someone help with this question plz

Calculate the heart rate of the dog in beats per minute
(edited 3 years ago)
To work it out, you need to figure out how many 'waves' there are per unit time.

It looks like there are 3 waves in 1s (i think thats what the x axis is referring to), therefore 3 * 60 (to get it in minutes) = 180bpm
Original post by app_
To work it out, you need to figure out how many 'waves' there are per unit time.

It looks like there are 3 waves in 1s (i think thats what the x axis is referring to), therefore 3 * 60 (to get it in minutes) = 180bpm

I did that but I got the answer wrong. The answer was a decimal? 160.something
Original post by sara.m12
I did that but I got the answer wrong. The answer was a decimal? 160.something

In that case maybe count how many lines there are between the 2 Q's and then work back from that.
That would mean there's 1 "beat" in x seconds, n then multiply up to get bpm.

I did it roughly n got something like 166.666....? ((idk if i counted all the lines tho))
Can someone properly explain this please I’m struggling with this question
Original post by Aeshakhan
Can someone properly explain this please I’m struggling with this question

So am I, I don't understand it
I did the calculation taking the point P as reference.
The first happened at 0.03s and the second at 0.39, therefore, the interval for a heartbeat is 0.36sec.
60 (seconds on a minute) / 0.36 = 166.6666...
You round it up to the closest whole number, which is 167 beats per minute.
I remember this question being on a past paper 1 2020 and on the mark scheme this is one of the acceptable answers.