The first thing we must do for this case is to define variables.
We have then:
x: weight of the big box
y: weight of the small box.
We now write the system of equations that models the problem:

We apply the graphic solution.
For this, the solution will be the cut point of both lines.
We have then that the solution occurs for the point:
Note: see attached image
Answer:
Weight of each large box: 15.5 Kilograms
Weight of each small box: 13.25 Kilograms
I= prt
I=$400 (0.06) (3)
I= 72
The 6% was changed into a decimal (0.06)
So I multiplied 400 x 0.06 x 3
The 400 would be the principal amount the 6% would be the rate and the 3 would be the time
Answer would have to be too the gallon of water would have to be2
Set up a proportion.
Let x = the number of students in 29970 who speak 3 or more languages.
285/19 = 29970/x Cross multiply
285 x = 19 * 29970
285x = 569430
x = 569430/285
x = 5415 students speak 3 languages.
(9/10)x3 feet
= (9/10)x36 inches
= 32.4 inches