What percentage by mass of beryllium is in beryllium aluminium sílicate? Give your answer to 2 significant figures,
Relative atomic mass (Ar) of Be = 9
Relative formula mass (Mr) of BesAl2(SiOs) = 537

Mike and mitchell decide to have a foot race. they mark off a stretch of 100 yards, and recruit cindy to work the stopwatch. after running the race and looking at the results, cindy declared that mitchell was the fastest. so how did the boys times compare?