In a recipe book, the time for fast roasting (f) in a hot oven is given as 20 minutes plus 40 minutes per kg (K). The time for slow roasting (S) in a moderate oven is given as 35 minutes plus 75 minutes per kg.
a Write down the equations. relating (1) F to K
(ii) S to K.
b Draw both graphs on the same axes for 0 ≤ K≤ 6.
c Use your graphs to estimate the cooking time for a
(1) 2.5 kg piece of meat (slow roasting)
(ii) 3 kg piece of meat (fast roasting).
d What was the weight of a piece of meat that took
3 hours 45 mins to cook in a hot oven?
e A 2kg piece of meat is put in the oven at 11am.
By mistake, the temperature is set halfway
between hot and moderate. By drawing a third
line on your graph, estimate when the piece of
meat will be cooked.
