Multiple choice algebra

Lisa has three classes that each last 50 minutes. what is the total number of minutes of the three classes

The value of the expression 16-^3/4 8 1/8 -6 6 1/40 1/64

Type the correct answer in the box. consider the system of linear equations below. rewrite one of the two equations above in the form ax + by = c, where a, b, and c are constants, so that the sum of the new equation and the unchanged equation from the original system results in an equation in one variable.