Traffic engineers have increased the capacity of the Krakkenbak Bridge to handle rush–hour traffic flow. The resultan...

ikarus July 14, 2020

Could someone diagram this question? I just can't seem to work it out, even knowing the correct answer.

shunhe July 23, 2020

Hi @melwoods and @ikarus,

Thanks for the question! So we know that the Krakkenbak Bridge now has an increased capacity to handle rush-hour traffic flow. We know that this wouldn’t have happened had the city not invested in computer modeling technology last year at the request of the city’s mayor; in other words, this wouldn’t have happened unless the city invested in computer modeling technology last year at the request of the mayor. Which means that we can diagram this statement (which is an “unless” statement) as

~Invest —> ~Increased traffic flow

Now for the next statement, we’re told that the city’s financial predicament wouldn’t have been resolved if the traffic flow across the bridge during rush hour hadn’t been increased. Well, this is a pretty straightforward if-then statement, so we can diagram this

~Increased traffic flow —> ~Resolve city’s financial predicament

And now we notice that these two statement share a common term, so we can link them in the following manner:

~Invest —> ~Increased traffic flow —> ~Resolve city’s financial predicament

And now look at (B), where we’re told that the city’s financial predicament wouldn’t have been resolved had the city not invested in computer modeling technology. In other words, if the city hadn’t invested, then the predicament wouldn’t have been resolved. This is just

~Invest —> ~Resolve city’s financial predicament

And we can get that from the above chain we made, so (B) can be properly inferred from the stimulus and is the correct answer.

Hope this helps! Feel free to ask any other questions that you might have.