Question 385316
Roger studied for x hours
Her sister studied for (x+5) hours.


Together, they studied for 30 hours in total. You need to set up an algebra equation to model this question:


x + (x+5) = 30


Now collect like terms:


2x + 5 = 30
2x = 30 -5
2x = 25
x = 12.5


So Roger studied for 12.5 hours. That means his sister must have studied for 12.5+5 = 17.5 hours.


Check your work. Does 12.5+17.5 = 30?


Yes, it does! So that means this must be correct.