Question 271038
F = B+4 
(F-5)+(B-5) = 48 Substitute F = B+4
(B+4-5)+(b-5) = 48 Simplify.
2B-6 = 48 Add 6 to both sides.
2B = 54 Divide both sides by 2.
B = 27 and...
F = B+4
F = 27+4
F = 31