Z-score for 30 = (30 - 25) / 5.8 = 0.8621
z-score for 20 = (20 - 25) / 5.8 = -0.8621
:
Note find probabilities from z-tables
:
Probability ( 20 < X < 30 ) = 0.8051 - 0.1949 = 0.6102
Answer:
B
Step-by-step explanation:

(Subtract 2L from both sides of the equation)
(Symmetric Property of Equality)
(Divide both sides of the equation by 2)
("Split" the fractions)
(Simplify)
Hope this helps!
Answer: 3000 stamps
Step-by-step explanation:
Given
Chris and Josh have 1800 stamps
Josh and Jessica have 2200 stamps
Jessica and Chris have 2000 stamps
Suppose Chris, Josh, and Jessica have
stamps

Thus, all three have 3000 stamps
I got 6.3 not sure if Im right