I am also not sure, because I also asked this question.
Answer:
21 and 22
Step-by-step explanation:
Let's work backward from that 81%: x/25 = 0.81 yields x = 20.25. Nominally, 20.25 / 25 = 0.81, but x must be an integer. Let's round 20.25 off to 20.
Thus, if Kalsom got 81%, it was a result of his having done 20 questions correctly.
81% corresponds to 20 questions correct;
82% to 20.5 questions correct, or, rounding up, to 21 questions correct;
83% to 20.75, or 21;
84% to 21 questions correct; this is the only result that makes sense (whole number of questions answered correctly)
85% to 21.25;
86% to 21.5;
87% to 21.75;
88% to 22 questions correct (this makes sense, unlike the last three)
89% to 22.25;
90% to 22.5;
91% to 22.75;
Assuming that the number of questions correct MUST be integer, then the possible number correct are 21 and 22, corresponding to 84% and 88% respectively.
We know that 60 minutes = 1 hour and 1 mile = 5280 feet. We just need to multiply and simplify:
651 miles/hour = 651 *5280/60 feet/minutes = 651*88 feet/minutes = 57288 feet/minutes
