Astore received a delivery that consists of x boxes that weigh 30 pounds each and y boxes that weigh 20 pounds each. there are 64 total boxes in the delivery and they have a combined weight of 1400 pounds. enter the number of boxes in the delivery that weigh 20 pounds.

Let the number of 30 pound boxes represented by =x

Let the number of 20 pound boxes be represented by =y

As given, there are 64 boxes so equation is:

or  ..... (1)

Total weight is 1400 pounds so equation becomes

 ...............(2)

Plug in the value of in 2nd equation

and

Hence, the number of boxes for delivery that weigh 20 pounds is 52.

51

step-by-step explanation:

73-22=51 the   mass number minus the amount of protons gives you the amount of neutrons