Respuesta :

o=orange
a=apple

equation 1
3o+a=$1.86
a=$1.86-3o

use a=$1.86-3o in equation 2

equation 2 
2o+3a=$2.15
2o+3($1.86-3o)=$2.15
2o+$5.58-9o=$2.15
$5.58-7o=$2.15
$5.58=$2.15+7o
$3.43=7o
$0.49=o

then use $0.49=o for equation 1.

equation 1

3($0.49)+a=$1.86
$1.47+a=$1.86
a=$0.39

so an apple is $0.39.