Question 1121323
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Basic algebra....<br>
let the capacity of the container in liters be x.<br>
Then the amount of water initially in the container is (2/5)x; when 3.5L of water are added, the amount in the container is (3/4)x.<br>
So
{{{(2/5)x + 3.5 = (3/4)x}}}<br>
Solve using basic algebra.<br>
Probably start by multiplying the whole equation by the least common denominator to get rid of the fractions....?