Answer:
40
Step-by-step explanation:
8*10^-3=0.003
2*10^-4=0.0002
0.003÷0.0002=40
I suppose a DJ wants to select 4 different songs, then there are: 12*11*10*9 = 11880 ways to choose them.
If the order of the songs he plays doesn't matter, there are: 
ways to choose them.
The rise or an increase in altitude is represented by positive sign and a decend or decrease in altitude is represented by negative sign.
First the helicopter descended 1200 feet. So the change in altitude will be -1200 feet.
Then the helicopter rose by 800 feet. So the change in altitude will be 800 feet.
Finally the helicopter descended by 450 feet. So the change in altitude will be -450 feet.
The net change in altitude will be the sum of all the above 3 changes.
Change in altitude = -1200 + 800 - 450 = -850 feet
The negative sign indicates a descend i.e. loss in altitude. So the net change in altitude was a loss of 850 feet.
$3 went to the men and and $2 to the bellboy. That's $5 in total, which is what the bellboy was supposed to give the men. So the $1 is with one of the men.
How many cups of walnuts are needed to make 3.75 batches of muffins? One batch of walnut muffins uses 1.33
1.13x3=3.39
