In the above figure, over the price range P5P6, demand is

In 1879 . President Rutherford B. Hayes had the first telephone installed in the White House, but it was rarely used because:

a. he didn't know what it was b. it kept breaking and no one could fix it c. hardly anyone else in Washington had a telephone, so there was no one to call or to call in d. hand written letters were considered a more correct form of correspondence

A firm's average fixed cost curve can never be U-shaped, even if its other average cost curves are U-shaped

a. True b. False Indicate whether the statement is true or false