3 hours because 39 divided by 13 equals 3 and to check just do 13x3 and it will get you to 39. in conclusion edgar will have to do 3 hours of hard work to get $39
Multiply the numbers being added then add the first number. 4X1=4, 4+1=5. 2X5=10, 10+2=12. 11X8=88, 88+8=96. I'm not sure how to get 40, though. Hope I could help.
