Pls help.

2018 SA1 Mathematics Paper 2 Question 15 Nanyang Primary School.

Rachel and Elijah received a fixed amount of money every month. In the first month, Rachel spent $5.60 and Elijah spent $2.80 per day. Rachel had $39.20 left when Elijah had spent all his money. In the second month, Rachel spent $2.80 per day and Elijah spent $5.60 per day. Rachel had $140 left when Elijah has spent all his money. How much money did Rachel receive every month?