Answer: 100% increase
Explanation:
You need the find the cost per bag in those weeks.
Three weeks ago, she could buy a bag for N5,700.
Three weeks after that, she could only buy half a bag for the same amount. A bag therefore costs:
= 5,700 ÷ 2/4
= N11,400
The percentage increase is:
= (11,400 - 5,700) / 5,700
= 100%