Using two normal number cubes, what is the probability of rolling numbers that add up to 4?
A. 1/18
B. 1/36
C. 1/12
D. 1/9

1/12

Step-by-step explanation:

When we roll 2 dice, there are 36 possible rolls

How can we get 4

1and 3, 3 and 1, 2 and2 = 3 different rolls

P( 4) = number of rolls with sum of 4/ total rolls

        = 3/36 = 1/12

he spend 5.1 minutes chatting with his friends

step-by-step explanation:

2/5+1/2=9/10

6/1-9/10=5 1/10

a 4/6 = 9/12   not proportional

step-by-step explanation:

to find which are not proportional, we can use cross products

if it is true, they are proportional.   if it is not true, they are not proportional.

a 4/6 = 9/12

4* 12 = 6*9

48 = 54

not this is not proportional  

b 2/3 = 12/18  

2* 18 = 3 * 12

36 = 36

this is proportional

c 5/4 = 10/8  

5*8 = 4*10

40 = 40

this is proportional

d 7/5 = 35/25

7*25 = 5 * 35

175 = 175

is proportional