16 thru 23 look wrong and 16 is absolutely wrong. You use this:https://www.mathpapa.com/algebra-calculator.html to work out the answers and it shows the steps and explains it to you better than I could. Good luck
For your answer the will be shown below
Unit rate= 9
258 cubic inches
Since the boxes are kind of on their own—>
First box: 7*2*12 = 168
Second box: 5*2*9=90
168+90 = 258
What you can do is multiply 400*20= 8,000. From here, we know that 399*20 is just one less group of 20 than 400. Therefore, we can subtract (1*20) from 8,000 to get the final answer.
8000-20=7980
Hope this helps!
