We conclude that the initial number of durians is 12.
How many durians were there at first?
Let's say that initially, we had N durians, such that these N durians have an average mass of 3.4kg.
When 2 durians (with an average mass of 1.3kg) more are added, the new average mass is given by:
(N*3.4kg + 2*1.3kg)/(N + 2)
And we know that the above amount is equal to 3.1kg, then we can write:
(N*3.4kg + 2*1.3kg)/(N + 2) = 3.1kg
Now we can solve this equation for N:
(N*3.4kg + 2.6kg) = 3.1kg*(N + 2)
N*(3.4kg - 3.1kg) = 6.2kg - 2.6kg
N*(0.3kg) = 3.6kg
N = (3.6kg)/(0.3kg) = 12
We conclude that the initial number of durians is 12.
If you want to learn more about mass:
https://brainly.com/question/1354972
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