Basically fibonachi is the 1st term+term before first term=2nd term 3rd term=1st term+2nd term 4th term=2nd term+3rd term etc
starting with t1=0 and t2=1 0,1 add them to get next 0+1=1 now we have 0,1,1 1+1=2 now we have 0,1,1,2 1+2=3 now we have 0,1,1,2,3 2+3=5 now we have 0,1,1,2,3,5 3+5=8 now we have 0,1,1,2,3,5,8 5+8=13 now we have 0,1,1,2,3,5,8,13 8+13=21 now we have 0,1,1,2,3,5,8,13,21
The two equations you want to write are for the two resources, tickets and dollars. We want to know the numbers of adult and senior tickets, so we assign the variables "a" and "s" to those numbers, respectively. We need to keep the meaning of these variables in mind as we write the equations.
a + s = 15 . . . . the sum of the numbers of tickets is 15 (resource = tickets)
The amount spent for tickets of a given type will be the number of tickets of that type, multiplied by the cost of tickets of that type. Then 6a represents the amount spent on adult tickets ($6 each for "a" number of tickets).
6a +4s = 76 . . . the total amount Beth spent on tickets (resource = dollars)
