6 1 class in a math exam, the average score of the whole class is 78, and the average scores of boys and girls are 75.5 and 8 1 respectively. The ratio of boys to girls in this class is ()
The answer is 6: 5.
Process: Number of boys *(78-75.5)= Number of girls *(8 1-87)
Number of boys: Number of girls = 6: 5