It is false that deserts advance linearly, in easily mappable patterns.
Deserts don't really have a pattern when they are advancing - there are so many ways they can do this.
Simply find the total medium cofees sold
then divide that by the number of medium cofees that weren't caffeinated
so..

then

so x will be 1.5 & 100 ÷ 1.5 = 66.666...
rounded is 67%
So hmmm x²+6x+8=0
alrite.. let's do some grouping now
( x² + 6x + [?]²) + 8 = 0
notice above, we have a missing fellow in order to get a perfect square trinomial... hmm who would that be?
let's take a peek at the middle guy of the trinomial.. 6x.. hmmm let's factor it, 2*3*x, wait a minute! 2 * 3 * x... we already have x² on the left-side, since the middle term is just 2 * the square root of the other two terms, that means that the guy on the right, our missing guy must be "3"
alrite, let's add 3² then, however, bear in mind that, all we're doing is borrowing from our very good friend Mr Zero, 0
so if we add 3², we also have to subtract 3², let's do so
(x² + 6x +3² - 3²) + 8 = 0
(x² + 6x +3²) + 8 - 3² = 0
(x+3)²=3² - 8
(x+3)² = 1
P=number of pages
we have to divide the number of photos by p
algebreaic expression represents the number of photosn on each page=60/p
60/p