A) 45
B) 35
C) 25
D) None of these
Correct Answer: B
Solution :
[b] Let Ravi got x marks in third unit test. |
\[\therefore \] Average marks obtained by Ravi |
\[=\frac{Sum\text{ }of\text{ }marks\text{ }in\text{ }all\text{ }tests}{Number\text{ }of\text{ }tests}\] |
\[=\frac{70+75+x}{3}=\frac{145+x}{3}\] |
Now, it is given that he wants to obtain an average of at least 60 narks. |
At least 60 marks means that the marks should be greater than or equal to 60. |
\[i.e.\frac{145+x}{3}\ge 60\] |
\[\Rightarrow 145+x\ge 60\times 3\] |
\[\Rightarrow 145+x\ge 180\] |
Now, transferring the term 145 to R.H.S., |
\[x\ge 180-145\Rightarrow x\ge 35\] |
i.e., Ravi should get greater than or equal to 35 marks in third unit test to get an average of at least 60 marks. |
\[\therefore \] Minimum marks Ravi should get = 35. |
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