Question

150(55-a) = 200(50-a)​

Answer 1

150(55-a) = 200(50-a)

or, 8250 - 150a = 10000 - 200a

or, -150a + 200a = 10000 - 8250

or, 50a = 1750

or, a = 1750/50

or, a = 35

Answer 2

8250-150a= 10000-200a
-150a+200a=10000-8250
50a=1750
a=1750/50
a=35