Please help! I really don't understand this, and if I could get the answer along with a really simple way to solve next questions like this it would be rlly helpful !!!!!!!

A fruit company packages its fruit into two types of boxes: large and small. This morning, the company made two deliveries. The table below shows the number of boxes in each delivery and the total weight (in kilograms).

1st delivery 2nd delivery
number of large boxes 3 9
number of small boxes 5 7
total weight (in kilograms) 116 238

Let x be the weight (in kilograms) of each large box.
Let y be the weight (in kilograms) of each small box.

(a) Write a system of equations that could be used to find the weight (in kilograms) of each type of box.
[ ]x + [ ]y = [ ]
[ ]x + [ ]y = [ ]

(b) How much does each type of box weigh (in kilograms)?
Weight of each large box: [ ] kilograms
Weight of each small box: [ ] kilograms

I know how to solve part a of the problem, at least. But part b is so difficult for me to understand, and I don't get it at all.