A) 24 minutes
B) 34 minutes
C) 125 minutes
D) 135 minutes
Correct Answer: B
Solution :
\[{{a}_{1}}={{a}_{2}}={{a}_{3}}.....\text{ }{{a}_{9}}=150\] \[{{a}_{1}}+{{a}_{2}}+{{a}_{3}}+....+{{a}_{9}}=1350\] \[{{a}_{10}}+{{a}_{11}}+......+{{a}_{n}}=45001350=3150\] \[\frac{n}{2}[2\times 150+(n-1)(-2)]=3150\] \[150n-{{n}^{2}}+n=3150\] \[{{n}^{2}}-151n+3150=0\] \[n=25\text{ }min\] hence total time\[=25+9=34\text{ }min\]You need to login to perform this action.
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