Çözüldü Sale, Profit, and Loss Problem

If a grocer makes a profit of b lira when he sells his eggs for 'a' lira each, and loses d lira when he sells them for 'c' lira each, how many eggs did the grocer sell in total?

A) (b - d) / (a - c)
B) b / [ c(a - d) ]
C) d / [ c(a - b) ]
D) (a - c) / (b + d)
E) (b + d) / (a - c)

e: Amount of eggs to be sold
M: Cost
e·a - M = +b....(I)
e·c - M = -d....(II)
Subtracting the equation (II) from (I), e·a - e·c = b - (-d) = b + d
Factoring the left side, e(a - c) = b + d
Dividing both sides by (a - c) yields e = (b + d) / (a - c).

Turkish Version of the Question:
Yumurtalarını, tanesi a liradan sattığında b lira kâr, c liradan sattığında ise d lira zarar eden bir bakkalın sattığı yumurta kaç tanedir?
https://alonot.com/wp-content/uploa...TİK-PROBLEMLER-TEST-SORULARI-VE-CEVAPLARI.pdf
(The last question with answers on the last page.)

WolframAlpha's Weird, Incorrect, and Incomplete Answer:
(Because of the letters given instead of numeric values)

https://i72.servimg.com/u/f72/19/97/10/39/equati11.png
https://www.wolframalpha.com/input?i=e*a - M = +b, e*c - M = -d, e = ?