math
posted by major .
10. A house painter can finish a house in 6 hours. His partner can finish the same house in 12 hours. Which of the
following is the number of hours it would have taken them to finish painting the house if they had worked together?
A. 3 hours
B. 4 hours
C. 6 hours
D. 9 hours

1/x = 1/6 + 1/12
x = 4