Question

Calculate the molarity of a solution obtained by mixing 100 mL of
0.3 M H2SO4 and 200 mL of 1.5M H2SO4

Answer 1

it is easy just apply the molarity equation $M_{1} V_{1} =M_{2} V_{2}$
or you are mixing them $M_{3} V_{3=} M_{1} V_{1} +M_{2} V_{2}$
you get
0.3*100+1.5*200=330M