Question : The half-life of a certain radioactive substance is 10 years. Suppose : 2163608
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.
Find the indicated composite for the pair of functions.
81) f(x) = 8.6(0.89)x
A) C = 7.654;
a = 1.89;
R = 11%
B) C = 8.6;
a = 0.89;
R = -11%
C) C = 7.654;
a = 0.89;
R = -11%
D) C = 8.6;
a = 1.89;
R = 189%
If P dollars are deposited in an account paying R percent annual interest, approximate the amount in the account after x years.
82) P = $19,000, R = 9%, x = 8 years
A) $37,858.69
B) $30,970.00
C) $34,732.74
D) $32,680.00
83) P = $560, R = 9%, x = 16 years
A) $2039.79
B) $1316.00
C) $1366.40
D) $2223.37
The amount P is deposited in an account giving R% annual interest compounded n times a year. Find the amount A in the account after t years.
84) P = $4000, R = 10%, n = 4, t = 1
A) $4415.25
B) $4862.03
C) $4203.78
D) $5856.40
85) P = $19,000, R = 5%, n = 2, t = 5
A) $24,321.61
B) $23,750.00
C) $24,249.35
D) $21,496.76
86) P =$4200, R = 6%, n = 4, t = 5
A) $4876.97
B) $7585.67
C) $13,469.97
D) $5656.79
87) P = $1710, R = 8%, n = 365, t = 8
A) $3222.56
B) $3202.80
C) $3165.09
D) $3242.75
88) P = $6000, R = 8.5%, n = 2, t = 5
A) $7388.08
B) $9021.94
C) $9136.77
D) $9097.29
Evaluate f(x) at the given value of x. Approximate the answer to the nearest hundredth.
89) ex, x = 3.1
A) 22.2
B) 24.53
C) 0.47
D) 1.13
90) ex, x = 2
A) 8.17
B) 5.44
C) 7.39
D) 0.69
Graph the function in the window [-4, 4, 1] by [0, 8, 1]. State whether it illustrates exponential growth or exponential decay.
91) f(x) = 2e0.7x
A) Growth
B) Decay
92) f(x) = e0.6x + 2
A) Growth
B) Decay
93) f(x) = 1.8e-1.4x
A) Decay
B) Growth
94) f(x) = 2.1e-x + 2
A) Growth
B) Decay
Solve the problem.
95) The amount of particulate matter left in solution during a filtering process decreases by the equation P(n) = 700(0.5)0.8n, where n is the number of filtering steps. Find the amounts left for n = 0 and n = 5. (Round to the nearest whole number.)
A) 1400; 44
B) 700; 44
C) 700; 22
D) 700; 11,200
96) The number of dislocated electric impulses per cubic inch in a transformer increases when lightning strikes by D(x) = 4000(3)x, where x is the time in milliseconds of the lightning strike. Find the number of dislocated impulses at x = 0 and x = 5.
A) 12,000; 972,000
B) 4000; 108,000
C) 4000; 972,000
D) 4000; 60,000
97) The number of bacteria growing in an incubation culture increases with time according to B(x) = 5100(5)x, where x is time in days. Find the number of bacteria when x = 0 and x = 2.
A) 5100; 15,937,500
B) 5100; 51,000
C) 5100; 127,500
D) 25,500; 127,500
98) The half-life of Cesium 134m is 3.0 hours. If the formula P(t) = ((1/2))t/3.0 gives the percent (as a decimal) remaining after time t (in hours), sketch P versus t.
A)
B)
C)
D)
99) A computer is purchased for $4600. Its value each year is about 79% of the value the preceding year. Its value, in dollars, after t years is given by the exponential function V(t) = 4600(0.79)t. Find the value of the computer after 6 years. Round to the nearest cent.
A) $697.87
B) $21,804.00
C) $1118.20
D) $883.38
100) The half-life of a certain radioactive substance is 10 years. Suppose that at time t = 0 , there are 29 g of the substance. Then after t years, the number of grams of the substance remaining will be N(t) = 29((1/2))t/20. How many grams of the substance will remain after 80 years? Round to the nearest hundredth when necessary.
A) 0.45 g
B) 1.81 g
C) 0.23 g
D) 0.91 g
