what are the values of x,y and xy if 0,019x + 0,029y + 0,01xy & x + y = 120000

Question

challenge question

Comments

Please check your question again. looks like something is missing.

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Yes, you’re right! I only see one actual equation, the other part being just an expression in x and y—no equals sign. A typo?

Answer 1

Assuming this expression is 0.019x+0.029y+0.01xy it can be written:

0.019x+0.019y+0.01y+0.01xy which is 0.019(x+y)+0.01y(1+x), or 2280+0.01y(1+x), because x+y=120000.

There is no equation accompanying the expression, so we can’t take this problem any further.

The expression further expands to 2280+0.01y(120001-y) or 2280+1200.01y-0.01y² which has a maximum value of 60000.5 for y (x=59999.5), giving a maximum value for the expression of 36002880. These numbers look so ungainly that it would appear that there is something fundamentally wrong with the details in the question even if the required equation were present.