A student scored marks in 5 subjects: 72, 68, 74, 70, and one unknown subject. If his average is 71, what is the missing mark?
Show answer & explanation
Correct answer: C
Explanation
Scores = 72, 68, 74, 70, x; Average = 71
According to the formula:
Average = (Sum of all scores) / (Number of scores)
71 = (72 + 68 + 74 + 70 + x) / 5
71 × 5 = 284 + x
355 = 284 + x
x = 355 − 284 = 71