"y varies directly as x" means y = kx
you do not know what k is yet, other than that it is some constant number.
Now plug in the given values, y=12 when x=4, in the equation
12 = 4k
=> k = 3
Now rewrite the equation with the k value you just found
y = 3k
Substitute 18 in place of x
y = 3(18)
y = 54
Answer:
The mean score is 87
Step-by-step explanation:
79x2=158
158-71=87
Slope as an (improper fraction)-9/7, it can’t be simplified
Answer:
- 8° per hour
Step-by-step explanation:
Given that:
Station A = - 6°
Station B = 2°
Rate of temperature change = x° / hour ; which is the same at both stations
Temperature at station A 3 hours after the recording is the same as the temperature in station B 4 hours after the recording ;
Temperature change in Station A:
-6 + 3x
Temperature change in station B:
2 + 4x
Temperature change in A = temperature change in B
-6 + 3x = 2 + 4x
Collect like terms
3x - 4x = 2 + 6
- x = 8
x = - 8
Hence, the rate of temperature change x in both stations is - 8° per hour
