Systems of equations

Question

Nari is checking items being shipped to the school store. The
shipment contains notebooks that cost $22 per box and mugs that cost $40 per box.
She counts 16 boxes, and the invoice states that the order totals $460. How many
boxes of each item were received?

Answer 1

Let N = number of boxes of notebook and M = number of boxes of mugs.

what are we given? 

1.) there are 16 boxes so 

M+N = 16.

2.) total order cost 460 so 

22N+40N = 460

 

solve 1 for one of variables. eg

M = 16-N

plug into 2 so 

22N+40(16-N)=460.

solve for N 

once you have N plug into 1 and you can get M.

best - David