Work = rate * time

We know that the machine worked a total of 14 hours and 2 hours more on Day 2 than Day 1 - so, 6 hours for Day 1 and 8 hours for Day2. The rates are r for Day 1 and (r+10) for Day 2. THus, we have:

Day 1 - 6r

Day 2 - 8(r+10)

The total made is 430 and that is comprised of 6r and 8(r+10) ==> 6r + 8(r+10) = 430

6r + 8r +80 = 430

14r = 350

r = 25

The question asks what the rate was for Day 1, which is r - Answer is C) 25