Question

The wholesale price p of e-tablet writing styluses in dollars is related to the supply x in thousands of units by

400p² − x² = 19575

If 5,000 styluses are available at the beginning of a week, and the price is rising at 30 cents per week, which one of the following statements is true?

A.Supply is falling at 168,000 styluses per week

B.Supply is rising at 168,000 styluses per week

C.Supply is falling at 192,000 styluses per week

D.Supply is rising at 168 styluses per week

E.Supply is rising at 192,000 styluses per week

Answer 1

we have

put x = 5 thousand,

now,

put x = 5, p = 7, dp/dt = 0.3 dollars,

Supply is rising at 168,000 styluses per week.