Help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Which solid figure has only 2 flat surfaces?

Tcecarenko [31]

I think its a cylinder

5 0

3 years ago

In a certain state, license plates each consist of 2 letters followed by either 3 or 4 digits. How many differen license plates

coldgirl [10]

Answer:

26 × 26 × 10 × 10 × 10 = 676 , 000 possibilities

Step-by-step explanation:

There is nothing stating that the letters and numbers can't be repeated, so all 26 letters of the alphabet and all 10

digits can be used again.

If the first is A, we have 26 possibilities:

AA, AB, AC,AD,AE ...................................... AW, AX, AY, AZ.

If the first is B, we have 26 possibilities:

BA, BB, BC, BD, BE .........................................BW, BX,BY,BZ

And so on for every letter of the alphabet. There are 26 choices for the first letter and 26 choices for the second letter. The number of different combinations of 2 letters is: 26 × 26 = 676

The same applies for the three digits. There are 10 choices for the first, 10

for the second and 10 for the third:

10 × 10 × 10 = 1000

So for a license plate which has 2 letters and 3 digits, there are: 26 × 26 × 10 × 10 × 10 = 676 , 000 possibilities.

Hope this helps.

8 0

3 years ago

A chemist has 200 mL of a 10% sucrose solution. She adds x mL of a 40% sucrose solution. The percent concentration, y, of the fi

user100 [1]

Answer:

The chemist needs to add 400mL of 40% solution.

Step-by-step explanation:

The equation

$y=\frac{0.1(200)+0.4x}{200+x} *100$

gives the percent concentration $y$ of the final mixture, when $x$ mL of the 40% solution are added.

Now we are asked, how many milliliters $x$ of the 40% solution should the chemist add to get final percent concentration $y=30$ ; this is just a matter of solving the equation

$30=\frac{0.1(200)+0.4x}{200+x} *100$

and we solve it the following way:

$30=\frac{0.1(200)+0.4x}{200+x} *100\\\\0.3 =\frac{0.1(200)+0.4x}{200+x}\\\\0.3(200+x)=0.1(200)+0.4x\\\\60+0.3x=20+0.4x\\\\40=0.1x\\\\x=\frac{40}{0.1} \\\\\boxed{x=400\:mL}$

Thus, the chemist needs 400mL of 40% solution to get 30% concentration of the final mixture.

7 0

4 years ago

A chemical spill is leaking into a river flowing 2 3/4 miles per hour. How long will it take the chemicals to reach a town locat

ExtremeBDS [4]

Answer:

$6\frac{3}{11}=6.27$ hours.

Step-by-step explanation:

We have been given that a chemical spill is leaking into a river flowing 2 3/4 miles per hour.

To find the time taken by chemical to reach the town we will divide distance of town from the spill by distance covered by chemical spill in one hour.

$\text{Time taken by chemical to reach the town}=17\frac{1}{4} \div 2\frac{3}{4}$