Answer:
a7 = 4
Step-by-step explanation:
r = a2/a1 = -128/256 = -1/2
an = a1·r^(n-1)
a7 = 256·(-1/2)^(7-1) = 256·(1/64)
a7 = 4
Further explain your question
You would do...
4 x 2.52 = 10.08
So it would be $10.08.
10 pair for first 10 for second.....total 80