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Numerical Inequalities · Question 60 of 79

Question 60

EasyOriginal question

A student scored 34 and 47 in two tests. What is the least she must score in the third test for her average to be at least 40?

Options for question 60

Show the answer and explanation
CorrectNot quiteAnswer A

Correct answer: A

Explanation

  1. 34+47+x3≥40\frac{34 + 47 + x}{3} \ge 40, so 81+x≥12081 + x \ge 120.

  2. x≥39x \ge 39: the least is 39.

Worth noting

40 aims for 40 in the third test alone; the first two already average 40.5.

Concept
An average as an inequality
Typical time
60 s
Your time
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The rule this testsInequalities from situations
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