Respuesta :

Answer:

62.5%

Step-by-step explanation:

average = sum of scores / number of scores

60% = [sum of 9 tests] / 9

[new average] = [sum of 10 tests] / 10

= ([sum of 9 tests] + 85%) / 10

= ((9 * 60%) + 85%) / 10

= 62.5%