How many minutes does it take John to type a words if he types at the rate of b words per minute? Choose one:
A) b/a
B) a/b
C) ab
D) 60a/b
E) b/(60a)
time*rate=job --&gt; time*b=a --&gt; time=a/b.   Answer: a/b.
<result>B</result>
How many minutes does it take John to type a words if he types at the rate of b words per minute?