Question 1184509
Let x be the number of tourists in the trip.  Then ⌈x/3⌉ gives the number of groups consisting of at most 3 tourists.  
Note that the last group may not even consist of 3 tourists, but is considered a group nonetheless, since a guide 
will be assigned to it and still be paid the 700 pesos.  For example, if there are 511 tourists then there are ⌈511/3⌉ = ⌈170.333...⌉ = 171 groups, 
although the last group has only 1 member tourist.


In other words, the cost of hiring guides as a function of the number of tourists x is given by  C(x) = 700⌈x/3⌉.


*** ⌈x⌉ is called the least integer function, or ceiling function for x.  Its graph is a 'step' function.