Betty and karen have been hired to paint the houses in a new development. working together, the women can paint a house in two-thirds the time that it takes karen working alone. betty takes 12 h to paint a house alone. how long does it take karen to paint a house working alone

6 hours

Explanation:

Let k = time it takes Karen to paint the house alone

then  according to the question,

(2/3)(k)(1/k + 1/12) = 1

⇒(2k/3)(1/k + 1/12) = 1

⇒(2k)(1/k + 1/12) = 3

⇒(2 + k/6) = 3

Multiplying both sides by 6:

12 + k = 18

k = 6 hours

therefore Karen takes 6 hours to complete the Task.

the first successful, urban blues recording, selling more than 75,000 copies, was made in year 1920.

mamie smith recorded the first commercially successful example of the urban blues,   with the recording of “crazy blues”."crazy blues" was recorded on august 10, 1920, in new york city. within a month of the release of “crazy blues” it had sold 75,000 copies.