12 people can wash 40 cars in 12 days. how many days will it take 4 people to wash 30 cars

1 answer:

7 0

First off, let's keep in mind we're looking for "days worth", how many days does it take to do an amount of cars.

so 12 folks can do in 12 days 40 cars, since each person is working every one of those 12 days, then each of those persons is working 12 days, now, there are 12 folks, that means the combined amount of days will be 12+12+12+12+12+12+12+12+12+12+12+12, or 12*12, 144 days worth, it takes them to do 40 cars.

so, to the same folks, how many days will it take them to do 30 cars?

$\bf \stackrel{12~folks}{\begin{array}{ccll}
days&cars\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
144&40\\
x&30
\end{array}}\implies \cfrac{144}{x}=\cfrac{40}{30}\implies \cfrac{144\cdot 30}{40}=x\implies 108=x$

that's 108 days worth for doing 30 cars.

for 12 folks, that'd be 108/12 or 9 days, 12 folks can do it in 9 days.

what about 4 folks only? 108/4 or 27 days.

You might be interested in

Help as soon as possible please

marta [7]

(3x + 5)° + (10x - 7)° = 180°

13x + (-2) = 180

13x = 180 + 2

13x = 182

x = 14

∠QRT = 3 * 14 + 5 = 42 + 5 = 47°

∠TRS = 10 * 14 - 7 = 140 - 7 = 133°

6 0

2 years ago

Write down the output y in terms of x

atroni [7]

Answer:

the x means 9

Step-by-step explanation:

6 0

2 years ago

Walk fifty meters at 30o north or east from the old oak tree. (2) Turn 45o to your left (you should now be facing 75o north of e

saw5 [17]

Answer:

A straight line of approximately 75 meters, 1.4º north

Step-by-step explanation:

Hi, let's make it step by step to make it clearer

1) If we walk 50 meters in 30º angle Northeast, assuming the Old Oak tree is the point 0,0 and we're dealing with vectors in $R^{2}$ . To say 30º Northeast is 30º clockwise (or 60º counter clockwise).

2) Then there was a the turning point to the left. If I turn to the left, on my compass 45º , I'll face 75º northeast.

3) Finally, the last vector leads to the treasure from the Old Oak Tree, i.e. the resultant.

So, let's calculate the norm which is the length of the each vector.

1) Graphing them we can find the points, then the components and then calculate the norm, the length of each vector.

Since the Oak Tree is on (0,0). The turning point (50,86.61) and the Rock (R=(1.4,74,85) we can write the following vectors:

$\vec{u}=\left \langle 50,86.61 \right \rangle\\\vec{v}=\left \langle -48.6,-11.76\right \rangle\\\vec{w}=\left \langle 1.4,74.85 \right \rangle$

Now, let's calculate each vector length by calculating the norm.

$\left \| \vec{u} \right \|=\sqrt{50^{2}+86.6^2}=100\\\left \| \vec{v} \right \|=\sqrt{(-48.6)^2+(-11.76)^2}=50\\\left \| \vec{u} \right \|=\sqrt{(1.4)^2+(74.85)^2}=74.86$

The path is almost 75 meters. And since it is less than 15º degrees to the left of the North (or to the right) its direction is still north of the Old Oak Tree.