Answer:
B. The problem involves a combination because the order in which the letters are selected does not matter.
Step-by-step explanation:
Computation technique is a method of statistics to find possible ways of combination. In computation technique it is assumed that order does not matter and letters will be selected at random. Permutation is a statistics technique to find possible ways of combination when the order does matter. Permutation technique cannot be used when order does not matter.
Cost of 1 set = 5t + 3j
so, the cost of 4 sets = 4(5t + 3j) = 20t + 12j Answer
Try using photomath it will explain on what to do.
Kind of lengthy but hope it helps! ;)