statistics, common question, grade 9 and 10

23/07/2016 Grade 10, Grade 9 634
  • x,y,7,8,9,10 are the scores of Jamil out of 10 in 6 math quizzes, where x is less than double y by 7.
  1. Calculate x and y if his average is 7.
  2. What score must Jamil get in the 7th quiz to let his average be 8?