# The most difficult problems

#### Number of problems found: 5941

• Powers 3
2 to the power of n divided by 4 to the power of -3 equal 4. What is the vaule of n?
• Driver
The driver of the car at a speed of 100 km/h faced the obstacle and began to brake with a slowing of 5 m/s². What is the path to stopping the car when the driver has registered the obstacle with a delay of 0.7 s?
• Brakes of a car
For the brakes of a passenger car to be effective, it is prescribed that a car moving on a horizontal road at a speed of 40 km. A car must stop on the track 15.4 m. What is the deceleration of the car?
• An equilateral
An equilateral triangle with a side 10 m represents a wooden platform standing in a lawn. A goat is tied to a corner with a 15 m rope. What is the maximum amount of grazing area available to the goat?
• Brakes
The braking efficiency of a passenger car is required to stop at 12.5 m at an initial speed of 40 km/h. What is the acceleration braking by brakes?
• The position
The position of a body at any time T is given by the displacement function S=t3-2t2-4t-8. Find its acceleration at each instant time when the velocity is zero.
• Domains of functions
F(x)=x2-7x and g(x)=5-x2 Domain of (fg)(x) is. .. . . Domain of (f/g)(x). ..
• Circle annulus
There are 2 concentric circles in the figure. Chord of larger circle 10 cm long is tangent to the smaller circle. What are does annulus have?
• Commission 2
Mr gomez sells used cellphones. His commission for every cellphone sold is 20%. If his total sales is Php 33850, how much is his commission? Please, please, please show your solution.
• Shuyen
Shuyen wanted to save some money. She deposited Php.300 in a bank which pays 0.5% interest per annum. After nine months, she needed the money to buy some gifts. How much will she be able to get if he withdraws all her money from the bank?
• Real estate 2
A real estate agent sold a lot for Php.550,000. If his agency pays at 10% commission, how much commission will he or she receive?
• Loan 4
Mr santos borrowed Php.18,000 at 1.5% interest for one year. What was the total amount he paid for the end of the 1-year term?
• Old laptop
The sale price of an old laptop is Php.11000. If 33 1/3% discount rate is given how much is the sale price of the laptop without the discount? Plese show your solution please. Php is Philippine peso
• Diofant equation
250x + 120y = 5640
• After 2
After we planted flowers in 2/5 of our garden, 24m remained unplanted. How many meters is the garden in total? If the total area of the garden is 1, the proportion of the remaining area is?
• Inverse matrix
Find out inverse by Gauss elimination or by reduction method. A=[2/3. 1 -3. 1/3]
• Cube root
Find cube root of 18
• Square root 2
If the square root of 3m2 +22 and -x = 0, and x=7, what is m?
• Sum of two primes
Christian Goldbach, a mathematician, found out that every even number greater than 2 can be expressed as a sum of two prime numbers. Write or express 2018 as a sum of two prime numbers.
• Population growth
How many people will be on Earth from two people for 5,000 years, if every couple has always 4 children, (2 boys and 2 girls) at the age of 25-35, and every man will live 75 years?

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