Answer:
12 staples
Step-by-step explanation:
So the first thing we have to do is find the G.C.D (Greatest Common Denominator) between 21/4 and 7/16 which of course is 16 so your new fractions would be 84/16 and 7/16.
Now we have to divide both numbers I just used a fraction calculator for this but basically you multiply 84/16 by the reciprocal of 7/16 which is 16/7 and simplify which equals 12.
So it would take 12 staples to bind the booklet