Help plz I need this answer quick

Question

A store recived a delivery that consists of x boxes that weight 30 pounds each and y boxes that weight 20 pounds each. There are 64 total boxes in the delivery and they have combined weight of 1400 pounds . Enter the number of boxes in the delivery that weight 20 pounds. ______boxes

Answer 1

x + y = 64       since there are 64 total boxes

30x + 20y = 1400

 

y = 64-x   from first equation

Substitute into 2nd equation and solve for x

 

30x + 20(64-x) = 1400

30x + 1280 - 20x = 1400

10x + 1280 = 1400

10x = 120

x = 12

 

y = 64-x = 64 - 12 = 52

 

There are 52 of the 20 pound boxes and 12 of the 30 pound boxes

 

Check:  12(30)+52(20)=360 + 1040 = 1400 pounds