#### Answer

The minimum score she needs on the final exam to obtain a B grade is 169.

#### Work Step by Step

The scores obtained from three 100-point tests are as follows:
75, 69 and 87
The scores obtained from 200-point test = X
The sum of three 100-point tests and 200-point test =
$75+69+87+X$
In order to obtain B grade,
$80=(75+69+87+X)/5$
X = 169