PLEASEEE HELPPPPPPPPPPPPPPPP!!!!!!!!!! MATH QUESTIONNNN

Question

A certain strain of influenza spreads rapidly until action by national and international health authorities eventually breaks the chain of transmission. During the outbreak the number of people P (in millions) infected t days after the onset of the disease rises and falls according to the formula P = -0.0108t² + 1.296t + 1.12. What is the maximum number of infected people over the course of the outbreak?

Group of answer choices

20

60

30

40

50

A certain radioactive isotope decays at a rate of 85% hourly. Determine the half-life of this isotope to the nearest minute. Use the formula A = Iekt where A is the amount at time t, I is the initial amount, and k is the decay constant unique to the substance.

Group of answer choices

18 min

14 min

256 min

35 min

22 min

The cost C for a business to manufacture N copies of a certain part is determined by the formula

C = 0.04N² - 8.504N + 567. How many copies of the part should the business manufacture to minimize cost?

Group of answer choices

110

115

112

108

106

Bob wants to build a fence around his rectangular garden. The length of the garden is three times its width. If the area of the garden is 100 square feet, how much fencing does Bob need? Round to the nearest tenth of a foot.

Group of answer choices

46.2 feet

41.8 feet

45.4 feet

40.0 feet

44.6 feet

 

Answer 1

Sounds like you just need a direction to go on these problems.

1) This is a parabola. Use t = -b/(2a) to solve for t and then substitute that into the equation to get P.

2)A = Ie^kt. Wants the time when A/I = 1/2. Take the natural log of both sides. ln(1/2)= tk where k = -0.87. Solve for t.

3) Another parabola. Use N = -b/(2a) as before and substitute that value into the equation to get C.

4) Let x = width and y = length. y = 3x. If Area = xy = 3x² = 100, then solve for x. The amount of fence needed is 2x + 2y = 2x +6y in feet.