
Alicia H. answered 10/18/15
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The best way to approach these types of questions is to translate the information into formula-form:
T = 2C (Terry types 2x as fast as Cecilia)
P = T - 5 (Paige types 5 WPM less then Terry)
R = T + 10 (Reggie types 10 WPM more than Terry)
R + C = T + P (The total number of WPM that Reggie and Cecilia type equals the total number of WPM that Terry and Paige type)
To use the last equation, we need to substitute for each variable (R, C, T, P) to get only one variable in the equation. If we rewrite the first equation, we can represent everyone in terms of T:
T = 2C
C = 1/2T
R + C = T + P
(T + 10) + (1/2T) = T + (T - 5)
Now we can solve for T:
1.5T + 10 = 2T - 5 (simplify)
1.5T = 2T - 15 (subtract 10 from both sides)
-0.5T = -15 (subtract 2T from both sides)
T = 30 (divide both sides by -0.5)
We now know that Terry types 30 WPM, and can use this information to solve for the others' typing speeds:
T = 30 WPM
C = 1/2(30) = 15 WPM
P = (30) - 5 = 25 WPM
R = (30) + 10 = 40 WPM
P = (30) - 5 = 25 WPM
R = (30) + 10 = 40 WPM
We can check our answers by plugging the above values into the equation below:
R + C = T + P
40 + 15 = 30 + 25
55 = 55