There are 51 students in class A and 49 students in class B. The average score of the two classes in a certain test is 81 points. The average score of class B is 7 points higher than the average score of class A. Then, what is the average score of class B?
甲班有51人，乙班有49人，某次考试两班平均成绩是81分，乙班平均成绩比甲班平均成绩高7分，那么，乙班平均成绩是多少分．
<gadget id="calculator">51 + 49</gadget>
<output>100</output>

<gadget id="calculator">100 * 81</gadget>
<output>8_100</output>

<gadget id="calculator">51 * 7</gadget>
<output>357</output>

<gadget id="calculator">8_100 + 357</gadget>
<output>8_457</output>

<gadget id="calculator">8_457 / 100</gadget>
<output>8_457/100 = around 84.57</output>

<result>8_457/100 = around 84.57</result>