assuming the printer is working at a direct proportion (and not inverse)
30 pages = 120 secs
(divide by 10)
3 pages = 12 secs
(divide by 3)
1 page = 4 secs
so 1p (is directly proportional to) 4s
the formula for direct proportion is
y ∝ kx
where y = the number of seconds and
where x = the number of pages
therefore if y = 4 and x = 1
then k = 4
meaning that the final proportion in
y = K x
where y = the number of seconds and
where x = the number of pages
(or you could write it as ... Sec = 4 x Pages)
