History of Space Exploration: Chapter 6, Exercise 1 — Possible Solution
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SEQUENCE
Program alarms 1201 and 1202 (rendezvous radar hardware issue); the computer
targeted a boulder-strewn area; Armstrong took manual control; he found clear
ground with 90 seconds of fuel remaining; touchdown with about 216 pounds of
usable fuel.

WHAT THE FIGURES DO NOT TELL YOU
They measure time and mass, and the source does not say how they relate or
when the 90 seconds was measured. Do not convert one into the other.