Make a graph and put a point at exactly (1,2) and then make a like at y=3 make a line through the point and you'll see that this is an undefined equation x cant equal all those numbers
This the are will be scaled by a factor of 25 which is 900 cm2
Area of the base and the top :(4x7) + (4x7) = 56
Lateral area of the front & the back = (4x12) + (4x12) = 96
Lateral area of the right & left = (7x12) + (7x12) = 168
TOTAL AREA = 56+96+168 = 320
Volume = 4x7x12 = 336
RATIO AREA/VOLUME = 320/336 . Simplify by dividing numerator and denominator by 16. Final result: AREA/VOLUME = 20/21
78×4000=312000
100×x=100x
312000÷100=3120
3120+4000=7120<----2nd month
7120×0.5=3560<----3rd month
4000<----1st month
4000+3560+7120=14680<----Your answer, this is the total of the three months.