It would take about 40 seconds for the temperature to reach 70°C and 44 second to reach 74°C.
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Linear equation</h3>
A linear equation is in the form:
y = mx + b
where y, x are variables, m is the slope of the line and b is the y intercept.
Let y represent the temperature of the metal bar after x seconds, hence:
Since the metal bar has an initial temperature of 30°C, hence:
b = 30, also m = 1°C (increase), The equation becomes:
y = 1(x) + 30 = x + 30
To reach 70°C:
70 = x + 30
x = 40 seconds
To reach 74°C:
74 = x + 30
x = 44 seconds
It would take about 40 seconds for the temperature to reach 70°C and 44 second to reach 74°C.
Find out more on Linear equation at: brainly.com/question/14323743
