You do what's in parentheses first, but everything is in parentheses so it's pretty much ineffective. In PEMDAS, addition and subtraction are coupled so you do them left to right. 6-1 is 5 and 5+7 is 12.

4 0

2 years ago

Read 2 more answers

8. There are 10 balls in a bag numbered from 1 to 10. Three balls are selected at random without replacement.

PIT_PIT [208]

Answer:

a. 720

b. 0.3

Step-by-step explanation:

Three balls are selected at random without replacement.

First ball can be selected in 10 ways

Second ball can be selected in 9 ways

Third ball can be selected in 8 ways

Thus, there are 10×9×8 =720 different ways of selecting three balls.

There are three cases that satisfy this condition

first ball picked is 5, the others are not
first ball is not 5, second is 5, third is not
first and second ball is not five, third ball is 5

Each probabilities are:

$\frac{1}{10} * \frac{9}{9} *\frac{8}{8} =\frac{1}{10}$
$\frac{9}{10} *\frac{1}{9} *\frac{8}{8} =\frac{1}{10}$
$\frac{9}{10} *\frac{8}{9} *\frac{1}{8} =\frac{1}{10}$

Thus, one of the balls selected is the number 5 is then $\frac{1}{10} + \frac{1}{10} + \frac{1}{10} = \frac{3}{10}$

5 0

3 years ago

the points in a coordinate plane are reflected in the y-axis. in general, every point (x,y) is mapped onto what point

Lisa [10]

Answer:

I'm not sure if this is right but y=x

Step-by-step explanation:

6 0

2 years ago