( a + b + c + d + e ) : 5 = a hoac b + 3000
( a + b + 10000 + 10000 + 10000 ) : 5 = a hoac b + 3000
( a + b + 30000 ) : 5 = a hoac b + 3000
1/5 a + 1/5 b + 6000 = a hoac b + 3000
2/5 a hoac b + 6000 = a hoac b + 3000
=> 3/5 a hoac b = 6000 - 3000 = 3000
a va b dong 5000 moi nguoi .
Ca 5 ban dong 40 000 dong