Chapter 6.5, Problem 46STP

To determine

To find: The proportion that is not used to calculate the number of minutes that would be taken by L.

Answer to Problem 46STP

Proportion $\frac{145}{550}=\frac{\text{w}}{3}$ could not be used to determine required minutes for typing 550 words.

Explanation of Solution

Given information: 

L types 145 words in 3 minutes and she has to type 550 words in asked minutes w .

Concept used:

Each ratio, in both conditions, will be set as: $\frac{\text{Total number of words typed}}{\text{Total minutes taken}}$ and should be equal to each other as both conditions are in proportion.

Calculation:

So, ratio representing first relation: $\frac{145}{3}$

Ratio representing second relation: $\frac{550}{\text{w}}$

Or actual proportion can be: $\frac{145}{3}=\frac{550}{\text{w}}$

  $\frac{145}{550}=\frac{3}{\text{w}}$ (on cross multiply)

  $\frac{\text{w}}{550}=\frac{3}{145}$ (on again cross multiply)

So, only proportion that could not be used to calculate total required minutes is $\frac{145}{550}=\frac{\text{w}}{3}$ as it does not fit any of the above proportion actually required to calculate required minutes.