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2 years ago

How many sets of 7 questions can be chosen from a file of 25 questions?

1 answer:

3 0

If all 25 questions are different,

When order of selection counts:
P(25,7)
=25!/(25-7)!
=15511210043330985984000000/6402373705728000
=2422728000

When order of selection does not count count:
C(25,7)
=25!/(7!*(25-7)!)
=15511210043330985984000000/(6402373705728000*5040)
=480700

You might be interested in

Thrice of product of five and b is reduced by 2

Diano4ka-milaya [45]

3 times the product of 5 and b is reduced by 2
3*(5*b)-2
15b-2

5 0

2 years ago

Joey's dog weighs 102.45 pounds. Jimmy's dog weighs 25.38 pounds less.

kari74 [83]

1.Since 5 is less than 8, borrow 1 from the next column to make 15.

2.Calculate 15 - 8, which is 7.

3.Calculate 3 - 3, which is 0.

4.Since 2 is less than 5, borrow 1 from the next column to make 12.

5.Calculate 12 - 5, which is 7.

6..<span>Calculate 9 - 2, which is 7.</span>

7.<span>Therefore, 102.45 - 25.38 = 77.07.</span>

8 0

2 years ago

Read 2 more answers

Ted is a long distance driver. It took him 30 min longer to drive 275km on the Trans-Canada highway west of Swift Current, Saska

IRISSAK [1]

Speed traveling west = x - 10 km /hr

275 / ( x-10) - 300 / x = 1/2

275 *2x - 300 (x-10)*2 = ( x-10) *x

550x - 600x +6000 = x^2 -10x

x^2 +40x - 6000 = 0

( x -60) ( x+100) = 0

x = 60

ANSWER East = 60 km/ hr West = 50 km /hr

CHECK

300 /60 = 5 hours

275 /50 = 5.5 hours

7 0

2 years ago

The sum of the measures of the angles of a triangle is 180. The sum of the measures of the second and third angles is five times

rusak2 [61]

Answer:

$x=30\\y=68\\z=82$

Step-by-step explanation:

x = measure of the first angle

y = measure of the second angle

z = measure of the third angle

The sum of the measures of the second and third (y+z) is five times the measure of the first angle (=5x)

$y+z=5x$

The third angle is 14 more than the second

$z=y+14$

And remember that the sum of these three angles must be equal to 180.

$x+y+z=180$

Let's take these equations

$y+z=5x\\z=y+14\\x+y+z=180$

If you take a look at the first equation, we have y+z = 5x and we have y+z in the third equation as well, we can replace that....

$x+y+z=180\\x+(y+z)=180\\x+(5x)=180$

Distribute the + sign

$x+5x=180$

Combine like terms;

$6x=180$

Divide by 6.

$x=\frac{180}{6}\\ x=30$

We have now defined that the measure of the first angle is 30º.

Let's take another equation... for example $z=y+14$

I'm going to take this one because if I replace x and z in the third equation, all I'll have left will be y.

$x+y+z=180\\30+y+(y+14)=180$

Distribute the + sign and Combine like terms;

$30+y+y+14=180\\44+2y=180\\$

Subtract 44 to isolate 2y.

$2y=180-44\\2y=136$

Now divide by 2.

$y=\frac{136}{2}\\ y=68$

We already have the value of x and y. Once again, replacing this in the third equation will leave us with z to solve for.

$x+y+z=180\\30+68+z=180\\98+z=180\\z=180-98\\z=82$

5 0

2 years ago

The art museum is 8 1/2 miles from Alison's house. Alison has ridden her bike 2/3 of the way there so far. How far how she gone?

ozzi

Alison is 2/3 of the way to the museum, so the answer is about 2/3 of 9, or 6 miles. Let's calculate it:

2 17 miles
---- * (8 1/2 miles) = -------------- She has ridden (17/3) miles, which is 5 2/3
3 3 miles.

8 0

2 years ago

Read 2 more answers