Question

Check my answer?
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Answer 1

Yes, your answer is almost correct.
That is a very unconventional way to form equations. The approach used is what I preach, especially for mental calculations.
The reasoning is as follows:
If all she bought were bananas, it would have cost 3.8*0.75=$2.85
However, if she bough apples, it would bring the cost up by (1.9-0.75)=1.15 for each pound of apples (p) she bought. So the total price is
1.15p+2.85=5.84.
Did you teacher explain this method of calculation before?