I can help you with the second part.
20M total in the population.
.25 are under 30
.45 are 30-45
.30 are over 45
From there you take the number of people from each age group and multiply by the percent of that age group that does not live in Tokyo, Hiro, or Yoko. (the "Other" group on your chart)
There are 5M people in the population under 30, from the chart we see that .125 of the population under 30 lives outside those three cities.
under 30 and outside the cities: (.125)(5M)=625,000
30-45 and outside the cities: (.325)(9M)=2,925,000
over 45 and outside the cities: (.20)(6M)=1,200,000
total population not in Tokyo, Hiro or Yoko = 625,000 + 2,925,000 + 1,200,000 = 4,750,000
the first question I tried twice and I do not understand how they got 11.8% as the answer.