A computer model compares two main sequence stars. Star X uses its fuel at 20 000 20\,000\,20000 times the rate of star Y, but its main sequence stage lasts 11000\displaystyle \frac{1}{1000}10001 as long.
In the model, the main sequence duration is proportional to the amount of usable hydrogen divided by the fuel-use rate.
Which statement is correct?
Star X has 19 00019\,00019000 times as much usable hydrogen as star Y.
Star X has 20 times as much usable hydrogen as star Y.
Star X has 20 000 00020\,000\,00020000000 times as much usable hydrogen as star Y.
Star X has 120\frac{1}{20}201 as much usable hydrogen as star Y.
75 exam-style questions on Edexcel GCSE Physics 7.3 Stars, covering 7.3.1 Evolution of stars similar to the Sun, 7.3.2 Evolution of massive stars, and 7.3.3 Observing the Universe. Each one has a worked solution and a mark scheme showing where the marks go.