Final answer:
You would need 60 crates each weighing 70kg to reach a total weight of 4200kg.
Step-by-step explanation:
To find out how many crates weighing 70kg each are needed to have a total weight of 4200kg, you need to divide the total weight by the weight of one crate.
Calculations:
Total weight = 4200kg
Weight of one crate = 70kg
Number of crates = Total weight ÷ Weight of one crate
Number of crates = 4200kg ÷ 70kg
Number of crates = 60
So, you would need 60 crates to have a total weight of 4200kg.