Here is the answer if you can't read my writing than just ask. also if you have any questions about how I got something feel free to ask
A $20 decrease followed by a $20 increase - original value
A 75% decrease followed by a 50% increase - less than the original value
A 50% increase followed by a 33 1/3% decrease - greater than the original value
A 60% increase followed by a 40% decrease - greater than the original value
A 100% increase followed by a 33 1/3% decrease - greater than the original
Let say the number is 0.5
Then, sum of this number will be 0.5+0.5=1
Now two is twice of 1.
Hence, it proved to be correct.
And difference between 5 and 1 is 4 which is less than 12. It also match the question condition.
Answer: The number is 1.
The answer is B The overall price change for the week
i hope it help