So we see the ratio of the sides of two similar octagons is 2:5 so let's say the first octagon has a side of 2 and the other has a side of 5. 2*8 = 16 and 5*8 = 40. 16:40 = 4:10 = and is again 2:5. So the answer is 2:5.
I think that is the answer because it says 2/5 where two rows are shaded and three more rows remain unshaded so, when you add that three and two it's altogether 5, so I think that is the answer, please check out the document I have uploaded.

Multiply through the second term by
:


Recall that
for all x :

If
, we can cancel a factor of it in the second fraction.

and this simplifies to

Let the number of minutes be m
29 + 0.04m ≥ 72.36
0.04m ≥ 72.36 - 29
0.04m ≥ 43.36
m ≥ 1084 minutes