For this case we have the following rule of three:
12 ----> 100%
8 ------> x
Clearing x we have:
x = (8/12) * (100)
x = 66.66666667% (percentage of correct answers)
For 20 baskets we have:
20 -----> 66.66666667%
x -------> 100%
Clearing x we have:
x = (100 / 66.66666667) * (20)
x = 30 attempts
Answer:
To make 20 canatas, 30 attempts must be made.