Since it doesn't give us a specific variable to use I'll just use y. and my phone doesn't have the less than or equal to sign so ill just say how to draw it i guess.
41. y (less than sign with line) 4.
42. y × (-7) > 42
43. y ÷3 - 5 (greater than sign with line) 11
and im not 100% sure on 44 so... anyway you probably know what the greater than or equal to sign and the less than or equal to sign are so. yeah hope it helped.
Answer: Then he has 84.50 in his bank account
Step-by-step explanation: elaborate???
Suppose he uses x mls of solution B.
0.5*1200 +0.1x=0.4(1200+x)
600+0.1x=480+0.4x
0.3x=120
x=400