#21 - During construction of the Quebec Bridge in 1907, the

[Adam Tyson]

It's implied in the combination of the last two statements of the stimulus, TZHUUMD22 - the rules of thumb had to be replaced by more rigorous math. The use of the comparative "more" in that last line indicates that the rules of thumb included at least some applications of mathematical analysis in order for the change to involve a "more rigorous" application. If the rules of thumb had no mathematical analysis at all, then the comparison would not make sense, and the author would have instead had to say "engineers would thereafter depend on rigorous applications of mathematical analysis."

And even if the rules of thumb had NO mathematical analyses, answer E would still be good! This is because whatever they did include, they were not sufficient to assure safety. Having zero math, if that is what they had, proved to be insufficient, as demonstrated by what happened with the Quebec bridge.

[TZHUUMD22]

Thank you for your detailed response Adam. I think LSAT usually makes the hard questions really word-sensitive. It is easy to ignore the implication of "more."

Thanks!

T