First multiply her average grade by the number of tests she took to find the total number of points she scored: 81 points * 2 = <<81*2=162>>162 points

Then subtract the number of points she scored on her first exam to find how many points she scored on her second exam: 162 points - 78 points = <<162-78=84>>84 points

# Answer

84
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Brittany got a 78 on her first test. After her second test, her average rose to an 81. What grade did she get on her second test?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
84
Brittany got a 78 on her first test. After her second test, her average rose to an 81. What grade did she get on her second test?
train