Question

If a student scores 71, 62 and x marks in 3 class test such that his average score lies between 65 to 70, then

A. 58<x<61
B. 62<x<77
C. 77<x<84
D. 51<x<57

Answer with method.​

Answer 1

Answer:

B. 62<x<77

Step-by-step explanation:

Answer 2

Given,

Student scores 71, 62 and x marks in 3 class test such that his average score lies between 65 to 70,

To find the correct relation, understand that average lies between 65 to 70. it means that average could be 66 as minimum and  69 as maximum.

Solution :

Take 66 as minimum average score,

$\[\begin{array}{l}\frac{{71 + 62 + x}}{3} = 66\\ \Rightarrow x = 198 - 133\\ \Rightarrow x = 65\end{array}\]$

Take 69 as maximum average score,

$\[\begin{array}{l}\frac{{71 + 62 + x}}{3} = 69\\ \Rightarrow x = 207 - 133\\ \Rightarrow x = 74\end{array}\]$

Hence, correct answer is option (B) i.e. $\[62 < x < 77\]$.