What is the value of the function, f(x)=x^2-5x when x=-5 ?
1 answer:
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x is 7.5 hours
Step-by-step explanation:
Ben, Tim, and Sam have to do a certain job
- Ben can finish the job in 5 hours
- Tim can finish the job in 6 hours
- Sam can finish the job in x hours
- The three of them can finish the job in 2 hours if they work together
We need to find x
∵ Ben can finish the job in 5 hours
∴ The rate of Ben =
∵ Tim can finish the job in 6 hours
∴ The rate of Tim =
∵ Sam can finish the job in x hours
∴ The rate of Sam =
They will working together to finish the job in two hours, that means the sum of their rate is equal to 1/2
∵ They can finish the job in 2 hours if they work together
∴
To add the fractions find the LCM for all denominators to make all fractions with same denominators
∵ The LCM of 5, 6 ans x is (5 × 6 × x) = 30 x,
- Divide it by each denominator to find the new numerators
∵ 30 x ÷ 5 = 6 x , 30 x ÷ 6 = 5 x , 30 x ÷ x = 30
- Change all the denominators to 30 x and then write the new
numerators of each fraction
∴
Add the numerators and put the sum over 30 x
∵
- By using cross multiplication
∴ 2(11 x + 30) = 1(30 x)
- Simplify the both sides
∴ 22 x + 60 = 30 x
- Subtract 22 x from both sides
∴ 60 = 8 x
- Divide both sides by 8
∴ 7.5 = x
∴ The value of x is 7.5 hours
x is 7.5 hours
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The approximate difference in the ages of the two cars, which depreciate to 60% of their respective original values, is 1.7 years.
Depreciation is to decrease in the value of a product in a period of time. This can be given as,
Here, (<em>P</em>) is the price of the product, (<em>r</em>) is the rate of annual depreciation and (<em>n</em>) is the number of years.
Two different cars each depreciate to 60% of their respective original values. The first car depreciates at an annual rate of 10%.
Suppose the original price of the first car is x dollars. Thus, the depreciation price of the car is 0.6x. Let the number of year is . Thus, by the above formula for the first car,
Take log both the sides as,
Now, the second car depreciates at an annual rate of 15%. Suppose the original price of the second car is y dollars.
Thus, the depreciation price of the car is 0.6y. Let the number of year is . Thus, by the above formula for the second car,
Take log both the sides as,
The difference in the ages of the two cars is,
Thus, the approximate difference in the ages of the two cars, which depreciate to 60% of their respective original values, is 1.7 years.
Learn more about the depreciation here;