Answer: 7
Step-by-step explanation: Cross multiply, so 15 times x and 21 times 5. 21 times 5 is 105 then you divide by 15 which gives you 7.
She is going to 5 classes 3×5 = 15 and 15÷3=5
Answer:
Step-by-step explanation:
Given that Heights of 10-year-olds, regardless of gender, closely follow a normal distribution with a mean of 55 inches and a standard deviation of 6 inches.
If X is height then X is N(55,6)
Z score would be 

b) 
c) Tallest 10% z = 1.28
X score =
inches
d)
i.e. 16.37% cannot go on this ride.
Answer:
110
Step-by-step explanation:
lets assume y is the angle next to x which should complete to form a 360.
50 + 25 + 35 + y = 360
y = 250
x + y = 360
x + 250 = 360
x = 110
Answer:
a
Step-by-step explanation:
the two lines intercept at 1,-2