The cost of 3 pens and 5 pencils is Rs.340. Also the cost of one pen and one pencil is in the ratio of 4:1 respectively. What is the cost of one dozen pens?	Select:
A) Rs.960	B) Rs.250	C) Rs.300	D) Rs.150	E) None of these
Explanation:   Let the cost of one pen is ‘4x’ and pencil is ‘x’   3 X 4x + 5x = Rs.340   12x + 5x = Rs.340   X = 340/17= 
<gadget id="calculator">340/17</gadget>
<output>20</output>
20   :. Cost of 1 pen= 4x = 4 x 20 = 80   :. Cost of 12 pens, i.e. (one dozen) = 80 x 12 = Rs.960   Rs.960nswer: Option Rs.960
<result>A</result>
The cost of 3 pens and 5 pencils is Rs.340. Also the cost of one pen and one pencil is in the ratio of 4:1 respectively. What is the cost of one dozen pens?