In this questions F1 score is given and we have to find the recall value. So rearrange the formula as following:
(1/F1 Score=(1/2) x ((1/Precision)+(1/Recall)) )
So,
(1/recall=((2/F1 Score)-(1/Precision)) or recall = (F1 Score x Precision) / (2 x precision – F1 Score)
recall= (0.85 x 0.82)/ (2 x 0.82 – 0.85) = 0.697/0.79 = 0.88
Study more about Evaluation at Evaluation Class 10