John and his family went out to eat at the bill of the food was $65 and it has a 20% tip what was the total cost other meal including the tip

$78

$65x.20=13

65+13=$78

option (b) is correct

step-by-step explanation:

to find the solution of this system, we need to convert it into reduced row-echelon form. we have,

after applying row operations r2 -> r2/2 and r3 -> r3/3, we get,

the formula of a midpoint between a abd b: