Lets call the rate at which the first panel absorbs solar energy x:
x = 9/7
To find out how much energy the panel will absorb in a certain number of hours, just multiply x by the time:
In 7 hours, energy = (9/7) * 7 = 9MJ
In 8 hours, energy = (9/7) * 8 = (72/7)MJ
Let's call the rate at which the second panel absorbs solar energy y. Therefore, we can write an equation, in x and y, using the information in the question:
5x + 5y = 41
We know what x is, so 5x = 5 * (9/7) = (45/7):
(45/7) + 5y = 41
5y = 41 - (45/7)
41 is the same as (41*7)/7 = 287/7:
5y = 287/7 - 45/7 = (287-45)/7 = 242/7
Divide both sides by 5 to find the value of y (in MJ absorbed per hours, MJ/h):
y = 242/35 = 6.914285714MJ/h
Let's call the time taken for the new panel to absorb 41MJ t:
ty = 41
We know what y is, so substitute that in and solve:
6.914285714t = 41
t = 41/6.914285714 ≈ 5.929752066 hours
I would like to express this value in the SI unit, which is seconds, s:
5.929752066 * 3600 = 21347.1s
