SimaQ
The equation (M + 6)/36 = (p – 7)/21 relates two temperature scales, where M is the number of degrees on one scale and P is the number of degrees on the other scale. Which of the following equations can be used to convert temperatures from the P scale to the M scale?
(A) M = (12/7)P + 13
(B) M = (12/7)P + 21
(C) M = (12/7)P – 12
(D) M = (12/7)P – 13
(E) M = (12/7)P – 18
The goal is to solve for \(M\) in terms of \(P\).
Given the equation:
\(\frac{M + 6}{36} = \frac{P - 7}{21}\)
First, multiply both sides by 36 to isolate \((M + 6)\):
\(M + 6 = \frac{36}{21}(P - 7)\)
Simplify the fraction \(\frac{36}{21}\). Both numbers are divisible by 3:
\(\frac{36}{3} = 12\) and \(\frac{21}{3} = 7\)
So, \(\frac{36}{21} = \frac{12}{7}\).
Now substitute this back into the equation:
\(M + 6 = \frac{12}{7}(P - 7)\)
Expand the right side:
\(M + 6 = \frac{12}{7}P - \frac{12}{7} \times 7\)
\(M + 6 = \frac{12}{7}P - 12\)
Finally, subtract 6 from both sides to solve for \(M\):
\(M = \frac{12}{7}P - 12 - 6\)
\(M = \frac{12}{7}P - 18\)
This matches option (E).
Answer: E