3 kitchen assistants can prepare 10 kg of vegetables in 45 minutes. How long would it take 15 assistants to prepare the same amount

This is an example of inverse proportion. The job that has to be done to to prepare the vegetables, That stays the same.

However, the more people there are to do the work, the quicker it will get done.

There is a constant to be found:

For 30 people:

my guess would be b and d, but i didn’t actually get out the pen and paper. lol