Answer:
D
Step-by-step explanation:
fastest way to find out the answer is to replace each solution with the xs of the equation and see if it is Equal to 4. the only solution that is equal to 4 is D)1/3
B. (x, y) to (1.5x, 2y) because you multiply x by 1.5 to get it to where it is and multiply y by 2
Given:
A man walks for x hours at a speed of (x + 1) km/h and cycles for (x - 1) hours at a speed of (2x + 5) km/h.
Total distance travelled is 90 km.
To find:
The value of x.
Solution:
We know that,
![Speed=\dfrac{Distance}{Time}](https://tex.z-dn.net/?f=Speed%3D%5Cdfrac%7BDistance%7D%7BTime%7D)
![Speed\times Time=Distance](https://tex.z-dn.net/?f=Speed%5Ctimes%20Time%3DDistance)
A man walks for x hours at a speed of (x + 1) km/h, so walking distance is
km
The man cycles for (x - 1) hours at a speed of (2x + 5) km/h, so the cycling distance is
km
Now,
Total distance = 90 km
![D_1+D_2=90](https://tex.z-dn.net/?f=D_1%2BD_2%3D90)
![(x+1)x+(2x+5)(x-1)=90](https://tex.z-dn.net/?f=%28x%2B1%29x%2B%282x%2B5%29%28x-1%29%3D90)
![x^2+x+2x^2-2x+5x-5-90=0](https://tex.z-dn.net/?f=x%5E2%2Bx%2B2x%5E2-2x%2B5x-5-90%3D0)
![3x^2+4x-95=0](https://tex.z-dn.net/?f=3x%5E2%2B4x-95%3D0)
![3x^2+19x-15x-95=0](https://tex.z-dn.net/?f=3x%5E2%2B19x-15x-95%3D0)
![x(3x+19)-5(3x+19)=0](https://tex.z-dn.net/?f=x%283x%2B19%29-5%283x%2B19%29%3D0)
![(3x+19)(x-5)=0](https://tex.z-dn.net/?f=%283x%2B19%29%28x-5%29%3D0)
![3x+19=0\text{ and }x-5=0](https://tex.z-dn.net/?f=3x%2B19%3D0%5Ctext%7B%20and%20%7Dx-5%3D0)
![x=\dfrac{-19}{3}\text{ and }x=5](https://tex.z-dn.net/?f=x%3D%5Cdfrac%7B-19%7D%7B3%7D%5Ctext%7B%20and%20%7Dx%3D5)
Time cannot be negative. So, the only possible value of x is 5.
Answer:
D
Step-by-step explanation:
Answer:
see the ans
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