isnt the solution wrong? or am i misinterpreting?

now the ques 2 of this set asks us to take the motnhs high - months low and divide it by avg.

now here. month's high and low of P is not 30 and 10 rather its 25 and 15. 25-15= 10

and so 10/20 = 0.5 which is less than one ...

i am getting the same for all other values.