Question

John took 3 exams so far this semester. He scored 45, 65 and 80 on those 3 exams . What score does he need on the fourth exam to average 70 or more on his exams?

Answer 1

Answer:

$He \: needs \: to \: score \: 90 \: or \: more$

Step-by-step explanation:

$\frac{x + 45 + 65 + 80}{4} \geqslant 70\Leftrightarrow x + 190 \geqslant 280\Leftrightarrow x \geqslant 90$