Exponential equation - practice problems - last page

Number of problems found: 139

Insert into GP
Between numbers 5 and 640, insert as many numbers as necessary to form a geometric progression, so the sum of the numbers you entered will be 630. How many numbers must you insert?
Half life
Determine the half-life of bismuth, when bismuth weight from the original weight of 32 g was only 2 grams in 242 minutes.
Geometric sequence
In the geometric sequence, is a₄ = 20 a₉ = -160. Calculate the first member a₁ and quotient q.
Lion or virgin
We toss the coin, and every throw fits a lion or a virgin with an equal probability of 1/2. Determine how much we have to make throws that, with the probability of 0.9, lions fell at least once.
Sum-log
The sum of two numbers is 19, and the sum of their logarithms (base 10) is 1.6. Determine these numbers.
Geometric sequence 3
In geometric sequence is a₄ = 40; a₉= 1280; s_n=2555. Calculate the first item a₁, quotient q, and n - number of members by their sum s_n.
Interest
What is the annual interest rate on your account if we put 32790 and after 176 days received 33939.2?
Exp
If sqrt[7](20²-12²) = sqrt[n](256), then n is:
Coordinate
Determine the unknown coordinate of the point M [x, 54] of the graph of the function f by rule: y = 3^x
Log
If log₄ x+ log₈ x = log_b x, what is b?
Crystal
The crystal grows every month at 1.2 permille of its mass. How many months does it take to develop from weight 177 g to 384 g?
Sequence
Calculate what member of the sequence specified by (5^n-2+15) has value 20.
Exponential equation
In the set R, solve the equation: 7^{-5 +19x}=4^{3 -20x}
Demographics
The population grew in the city in 10 years from 30000 to 34000. What is the average annual percentage increase in population?
Compound interest
Calculate the time when the deposit in the bank with interest 2.6% p.a. doubles.
Radioactivity
After 113 hours decreases, the activity of a radioactive substance to 1/6 of the initial value. What is the half-life of the substance?
Exponential equation
Solve exponential equation (in real numbers): 2^3x-6=9
Computer revolution
When we started playing with computers, the first processor, which I remember was the Intel 8080 from 1974, with the performance of 0.5 MIPS. Calculate how much percent of a year rose CPU performance when Intel 486DX from 1992 has 54 MIPS. What would
When will I be a millionaire?
Barry monthly sends 280 euros to the bank, which he deposits bear interest of 2.1% p. A. Calculate how many months Barry must save to save 1000000 euros. Inflation, interest rate changes, or bank failures are ignored.

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