Question 318828
Let A be the cost of an apple, R the cost of an orange.
"4 apples and 2 oranges equals $1 (100 cents)"
1.{{{4A+2R=100}}}
"2 apples and 3 oranges equals $0.70 (70 cents)"
2.{{{2A+3R=70}}}
Multiply eq.2 by (-2) and add to eq. 1 to eliminate A,
{{{-4A-6R+4A+2R=-140+100}}}
{{{-4R=-40}}}
{{{R=10}}}
Then use either equation to solve for A. 
{{{4A+2R=100}}}
{{{4A+2(10)=100}}}
{{{4A+20=100}}}
{{{4A=80}}}
{{{A=20}}}
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Apples cost 20 cents ($0.20) and oranges cost 10 cents ($0.10).