exam Maths Puzzle Numerical Ability

i have tryed to help my son and question ft46 was easyer but i cant figure FT47 out what am i missing

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exam Other Question

in 2006, about 25,500,000 children between the ages of 12 and 17 lived in the United States. That was about 8.3% of the entire U.S. population. find the approximate 2006 U.S.population what is 2x-3y=12
x=4y+1

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