In the equation given, what is a+b?

I know you have to do it by making the numbers into the same 2 and 3 bases (ex. 6 is 2×3, 18 is 3²×2) but i cant finish it. Help​

Emma will roll two number cubes labeled 1 through 6. she will record the sum of the two numbers after each roll. she will roll the two cubes 540 times. how many times should emma expect the sum to equal 5?

Can somebody me out with this question

15m is what percent of 60m; 3m; 30m; 1.5 km? the last one is km not m