HELPP---> FINDING SCALE OF A GRAPH

[mtbrain]

hi!
can someone give me a method of finding the scale of graph???
i'm having difficulties!
especially in Biology M/J 09 paper((((http://www.freeexampapers.us/IGCSE/Biology/CIE/2009%20Jun/0610_s09_qp_6.pdf)))), Question 2)c)i)  ;; and I only have 3 days!! HELP PLEASE

[nid404]

Choosing a scale can be quite a headache.

The important thing you should know when you choose a scale is that it should cover more than half the graph paper.

For this particular question....your only bothered abt the Y-axis scale...the data shows max heart rate is 200. There are 14 lines(14cm) on the Y axis.

You can conveniently choose 20 for 1cm, it will cover a good deal of space.

I gave this very paper last year and scored an A*