# Exponential equation - math word problems

#### Number of problems found: 54

• Decibel
By what percentage does the sound intensity increase if the sound intensity level increases by 1 dB?
• Investment
1000\$ is invested at 10% compound interest. What factor is the capital multiplied by each year? How much will be there after n=12 years?
• The city 3
The city has 22,000 residents. How long it is expected to have 25,000 residents if the average annual population growth is 1.4%?
• Powers 3
2 to the power of n divided by 4 to the power of -3 equal 4. What is the vaule of n?
• Water lilies
Water lilies are growing on the pond and their number is doubled every day. The whole layer is covered in 12 days. How many days will it cover 8 layers?
• Geometric sequence 3
In geometric sequence is a8 = 312500; a11= 39062500; sn=1953124. Calculate the first item a1, quotient q and n - number of members by their sum s_n.
• An investment
How long will it take for an investment to double at a simple interest rate of 5.10% p. A. ? Express the answer in years and months, rounded up to the next month.
• Sum-log
The sum of two numbers is 32, the sum of their logarithms (base 10) is 2.2. Determine these numbers.
• 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.
• Growth of wood
The annual growth of wood in the forest is estimated at 2%. In how many years will make the forest volume double?
• If you 4
If you deposit \$2500 in an account paying 11% annual interest compounded quarterly, how long until there is the \$4500 in the account?
• Six speeds
A drilling machine is to have 6 speed ranging from 50 to 750 revolution per minute. If the speed forms a geometric progression, determine their values.
• If you 2
If you deposit \$4000 into an account paying 9% annual interest compounded monthly, how long until there is \$10000 in the account?
• Compound Interest
If you deposit \$6000 in an account paying 6.5% annual interest compounded quarterly, how long until there is \$12600 in the account?
• Semiannually compound interest
If you deposit \$5000 into an account paying 8.25% annual interest compounded semiannually, how long until there is \$9350 in the account?
• Insert into GP
Between numbers 5 and 640 insert as many numbers to form geometric progression so sum of the numbers you entered will be 630. How many numbers you must insert?
• Annual pension
Calculate the amount of money generating an annual pension of EUR 1000, payable at the end of the year and for a period of 10 years, shall be inserted into the bank to account with an annual interest rate of 2%
• Annual growth
The population has grown from 25,000 to 33,600 in 10 years. Calculate what was the average annual population growth in%?
• Crystal
The crystal grows every month 1.2 permille of its mass. For how many months to grow a crystal from weight 177 g to 384 g?
• Lion or virgin
We toss coin, every throw fits lion or a virgin with equal probability 1/2. Determine how much at least we have to make throws that with probability 0.9 lion fell at least once.

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