• # question_answer The total cost of 12 pens and 5 pencils is equal to Rs 111. Also the cost of 1 pencil is Rs 5 less than the cost of 1 pen. What will be the cost of 8 pens and 9 pencils? A)  Rs 89              B)  Rs 91 C)  Rs 97              D)  Rs 98

Let the cost of 1 pencil be $x$. $\therefore$ Cost of 1 pen $=(x+5)$ Now, according to the question, $12(x+5)+5x=111$ $\Rightarrow$ $12x+60+5x=111$ $\Rightarrow$ $17x=111-60=51$ $\therefore$ $x=\frac{51}{17}=3$ $\therefore$ Cost of 1 pencil = Rs 3 and cost of 1 pen $=(3+5)=\text{Rs}\,\,8$ $\therefore$ Total cost of 8 pens and 9 pencils $=(8\times 8+9\times 3)$ $=(64+27)=\text{Rs}\,\,91$