If we toss a pair of dice, what is the probability that a sum of 7 will appear?
A./ 7/36
B. 1/6
C. 1/2
D. 1/36
Four coins are tossed at the same time. What is the probability that exactly 3 heads will appear?
A. 1/2
B. 1/4
C. 1/16
D. 1/8
36 possible rolls
6 1
5 2
4 3 are all 7's and two ways of rolling each of the, 6/36 = 1/6
So basically we first need to figure out how much pairs that add to 7.
1,6
6,1
2,5
5,2
3,4
4,3
There are 6*6 = 36 possible outcomes, so 6/36 = 1/6
See guest's post below for 2).
If you don't understand anything feel free to ask.
Hmmmm 16 possibilities for the coin toss
there are 4 possibles for EXACTLY 3 heads
HHHT
HHTH
HTHH
THHH 4 OUT OF 16 = 1/4
Intresting point.
There are 4 ways of only 1 heads,
HTTT
THTT
TTHT
TTTH
2heads,
HHTT
HTHT
HTTH
THHT
THTH
TTHH
3 heads
HHHT
HHTH
HTHH
THHH
4 heads
HHHH
0 heads
TTTT
Good point it's 4/16
I'll revise my answer thanks for the correction!