How i find equivalent fractios numbers are 2/6 and 3/4

Which shows the correct solution of the equation 1/2a+2/3b=50, when b=30?

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.

Pls what is the decimal equivalent of 5 over 9? select one: a. 0 point 5 bar over top of 5 b. 0 point 6 bar over top of 6 c. 0 point 8 bar over top of 8 d. 0 point 9 bar over top of 9