Let's say the manufacturer spent $X million in production of acoustic guitars and $Y million for electric guitars in 1999. so the total is X + Y = 89. This is the first equation.
We know that the company spent producing acoustic guitars was ?$50 million more than it spent on producing electric? guitars. From here we can write down the second equation as: X = Y + 50.
let's write both equations as follow:
X + Y = 89
X= Y + 50
Let's replace X in the first equation with "Y+50", so we can calculate the value of Y:
Y+50 +Y= 89
2Y+50 = 89
2Y + 50 -50 = 89-50
2Y = 39
2Y/2 = 39/2
Y = 19.5 (company spent $19.5 million in production of electric guitars in 1999).
X = Y + 50 = $19.5 +$50 =$69.5 (company spent $69.5 million in production of acoustic guitars in 1999).