X+b What values make the inequality R s0 true?
O+ttH
+
-7-6-5 -4-3 -2-1 0 1 2 3 4 5
-7-6-5-4- 2-1 0 1 2 3 4 5 6 7
-7-6-5-4-3-2-1 01 23 4 5
7
-4-3-2-1
4

We know the value of Tuesday, let's make this variable "T", is 70.
We also know the value of Monday, let's make this variable "M", is 15 minutes longer than the value of Tuesday.

Using these variables and the information provided we can make the expression: M=T+15
M=70+15
M=85
This means Eleni worked for 85 minutes on Monday.
Hope this helps :)