Answer this please. I'm struggling to get it's answer.

Let’s quickly write the equations

B1 + B2 = 14

B1 + B3 = 15

B2 + B4 = 16

B3 – B4 = 10

by adding all equations

B1 + B2 + B3 = (14 + 15 + 16 + 10 )/2 = 55/2 = 27.5

B3 = 27.5 – (B1 + B2) = 27.5 – 14 = 13.5 => B3 = 13.5

B2 = 27.5 – (B1 +B3) = 27.5 – 15 = 12.5 => B2 = 12.5

B1 = 14 – B2 = 14 – 12.5 = 1.5 => B1 = 1.5

B4 = B3 – 10 = 13.5 – 10 = 3.5 => B4 = 3.5

Regards