Using what you know about variables and re-assignment you should be able to trace this code and keep track of the values of a, b, and c as they change. You should also have a sense of any possible errors that could occur.

Explanation:

The missing program is given below

var a = 3;

var b=7;

var c = 10;

a=a+b;

b=a+b;

c=a+b;

console.log("a:" + a + "b:" + b+"c:" + c);

In the program  a is assigned a value 3, b is assigned a value of 7, c is assigned a value 10;

a = a+ b; so here a = 3+7 = 10. New value of a = 10

b = a+b; so here b=10+7 = 17. New value of b = 17

c = a+ b; so here c = 10 + 17 = 27. New value of c = 27

So the final line will log a = 10, b = 17, c = 27.