To determine how much will it take to clean a 120ft driveway considering that it took him 2hs to clear 10ft and that the cleaning rate is constant, you can use cross multiplication:

10ft______2hs

120ft_____xhs

If the cleaning rate is the same, then the ratios between both are the same:

$\frac{2}{10}=\frac{x}{120}$

From this expression, you can determine the time by multiplying both sides of the equal sign by 120

$\begin{gathered} 120(\frac{2}{10})=\frac{120x}{120} \\ 24=x \end{gathered}$

It will take him 24 hours to clear the 120ft driveway.

5 0

1 year ago

Need help with my math, please jog my memory.. its been so long since I've done scientific notation. Just answer a few,, thats a

Scrat [10]

Answer:

Down below, look at the explanation, those are the answers.

Step-by-step explanation:

1) 8 * 10 to the power of 0

2) 5.4 * 10 to the power of 1

3) 2 * 10 to the power of -2

4) 2.29 * 10 to the power of 2

5) 1.87 * 10 to the power of 2

6) 4.52 * 10 to the power of -1

7) 6.009 * 10 to the power of -3

8) 4.52 * 10 to the power of 2

9) 3.5710 * 10 to the power of 4

10) 5.026 *10 to the power of -5

11) 7.87 * 10 to the power of 5

12) 4.52 * 10 to the power of 1

13) 9.345 * 10 to the power of 2

14) 4.52 * 10 to the power of -7

15) 1.1235 * 10 to the power of 10

Hope it helps!!

Let me know if I'm wrong...

8 0

3 years ago

Clue #1: The sum of the digits of a 3 digit number is 20. Clue #2: The tens digit is 2 less than the hundreds digit. Clue #3: Th

o-na [289]

Answer: The number is 974

Step-by-step explanation:

First, any 3 digit number can be written as:

N = a*100 + b*10 + c

Where a, b, and c are single-digit numbers.

a is the hundreds digit

b is the tens digit

c is the unit digit

We can write the clues as:

#1: a + b + c = 20

#2: b = a - 2

#3: c = a + b - 12

Then we have a system of equations:

a + b + c = 20

b = a - 2

c = a + b - 12

To solve this, we need to isolate one of the variables in one equation and then replace this in the other equations, we can see that b is already isolated in the second equation, then we can replace that in the first and third equations:

a + (a - 2) + c = 20

c = a + (a - 2) - 12

Now we can see that c is isolated in the second equation, then we can replace that in the first one to get:

a + (a - 2) + (a + (a - 2) - 12) = 20

Now we can solve this for a:

a + a - 2 + a + a -2 - 12 = 20

4*a - 16 = 20

4*a = 20 + 16

4*a = 36

a = 36/4 = 9

With this, we can find the values of b and c.

b = a - 2 = 9 - 2 = 7

c = a + b - 12 = 9 + 7 - 12 = 4

Then the 3-digit number is:

N = a*100 + b*10 + c = 9*100 + 7*10 + 4 = 974

N = 974

6 0

3 years ago