B. 4x + 6y = 160. x is the number of tables of 4. y is the number of tables of 6.
A. 4(25) + 6(10) = 160. 25 tables of 4 and 10 tables of 6. 4(22) + 6(12) = 160. 22 tables of 4 and 12 tables of 6. Split 160 into two number (60 and 100, etc). One has to be divisible by 4 and the other has to be divisible by 6.