Question 1068101
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The total mas of 12 mangoes is 12*1.5 = 18 kg = 18000 g.


Now you have a proportion


{{{81/18000}}} = {{{x/11}}}


Solve it for x, the unknown under the question, and you will get the answer:


x = {{{(81*11)/18000}}}.



I do not touch here the question who and how will sell you 11 g of mango.