Answer:
80 pages
Step-by-step explanation:
We can use ratios to solve
168 papers x papers
------------------ = -----------------
21 minutes 10 minutes
168*10 = x * 21
1680 = 21x
Divide each side by 21
1680/21 = 21x/21
80 = x
the missing fact is 7×4=42
15
3x3=9
so therefore you need to multiply 2 by 3=6
9+6=15
C