60 items were for sale because you need to add together the amounts that were sold plus what was left over, giving you everything that they had for sale.
I THINK THE CORRECT ANSWER IS A!!!
Answer:

Step-by-step explanation:
When x = 3, y = 13
When x = 5, y = 37
Subtract both y-values to find the change:
37 - 13 = 24
Average of the change:
= 12
6r - 3t = 6 /*8
6r + 8t = - 16 /*3
48r - 24t = 48
48r + 24t = - 48
---------------------- +
96r = 0
r = 0
t = ( -16 + 6r)/8 = - 16/8 = - 2
6²+8²=c²
36+64=c²
c²=100
c=10