Answer:
80 feet
Step-by-step explanation:
Given:
Initial speed of the car (
) = 40 ft/sec
Deceleration of the car (
) = -10 ft/sec²
Final speed of the car (
) = 0 ft/sec
Let the distance traveled by the car be 'x' at any time 't'. Let 'v' be the velocity at any time 't'.
Now, deceleration means rate of decrease of velocity.
So, 
Negative sign means the velocity is decreasing with time.
Now,
using chain rule of differentiation. Therefore,

Integrating both sides under the limit 40 to 0 for 'v' and 0 to 'x' for 'x'. This gives,
![\int\limits^0_{40} {v} \, dv=\int\limits^x_0 {-10} \, dx\\\\\left [ \frac{v^2}{2} \right ]_{40}^{0}=-10x\\\\-10x=\frac{0}{2}-\frac{1600}{2}\\\\10x=800\\\\x=\frac{800}{10}=80\ ft](https://tex.z-dn.net/?f=%5Cint%5Climits%5E0_%7B40%7D%20%7Bv%7D%20%5C%2C%20dv%3D%5Cint%5Climits%5Ex_0%20%7B-10%7D%20%5C%2C%20dx%5C%5C%5C%5C%5Cleft%20%5B%20%5Cfrac%7Bv%5E2%7D%7B2%7D%20%5Cright%20%5D_%7B40%7D%5E%7B0%7D%3D-10x%5C%5C%5C%5C-10x%3D%5Cfrac%7B0%7D%7B2%7D-%5Cfrac%7B1600%7D%7B2%7D%5C%5C%5C%5C10x%3D800%5C%5C%5C%5Cx%3D%5Cfrac%7B800%7D%7B10%7D%3D80%5C%20ft)
Therefore, the car travels a distance of 80 feet before stopping.
Answer: 2.8%
Step-by-step explanation:
Give, In a certain month a family spent $750 on food
In third month the family spent $729 on food .
i.e. Expenditure on food in a certain month = $750
Expenditure on food in third month = $729
Decrease in monthly spending on food = (Expenditure in a certain month )- (Expenditure in third month )
= $750 - $729
= $21
Now , the percentage decrease in the month spent on food will be :

Hence, the percentage decrease in the month spent on food is 2.8%.
The answer to this problem is 51
1. You have to distribute the 61n into the parenthesis.
2. You get 61nx+170.8n=9.6