Part A:
Since each cutting machine cuts 105 parts in three minutes, let’s figure out how much they all cut in 3 minutes
105 • 6 = 630
We are looking for only in 1 minute, so divide this by 3
630 / 3 = 210
Answer is C, 210 parts
Part B:
Let’s figure out how many stamps one machine can make in a minute
24 • 3 = 72
Then let’s find out how many all can make in a minute
72 • 4 = 288
Make an equation to find how long it will take to make 4320 stamps
288x = 4320
Divide
x = 15
The answer will be B, 15 minutes