Answer:3/20
Step-by-step explanation:
Heads=Boy
Tails=Girl
If the first 3 students are boys, all 3 coins must be heads.
Because in 3 of these experiments, the coins all land on heads, and there are 20 experiments completed, 3 out of the 20 experiments are 3 boys; 3/20.
First, note that 
Then use the formula for the sum of perfect cubes:
Therefore,
The quadratic trinomial 
couldn't be factored anymore, so the expression 
has two factors 
and 
Answer: correct choice is A.
I hope it's about 1.8 sec
Answer:
2
Step-by-step explanation:
6-x/2=4
6-x=4*2
6-x=8
x=2
