I brought 30 books on Mathematics, Physics, and Chemistry, priced at Rs.17, Rs.19, and Rs.23 per book respectively, for distribution among poor students of Standard X of a school. The physics books were more in number than the Mathematics books but less than the Chemistry books, the difference being more than one. The total cost amounted to Rs.620. How many books on Mathematics, Physics, and Chemistry could have been bought respectively? Choose the correct choice from the following: A) 5, 8, 17 B) 5, 12, 13 C) 5, 10, 15 D) 5, 6, 19 E) None of these
Explanation :   Given, Total amount=620 ( last digit is 0 ).   So find the last digit of product number of books and price of one book.   option 1, 7*5 + 9*8 + 3*7 = 5+2+1= 
<gadget id="calculator">5+2+1</gadget>
<output>8</output>
last digit 8 is not 0.   option 2, 7*5 + 9*2 + 3*3= 5+8+9 = last digit is not 0.   option3, 5*7 + 10*9 + 5*5 = 5+0+5= last digit is 0.   option4, 5*7 + 6*9 + 3*9 = 5+4+7=6 last digit is not 0.   Hence, only 3rd option satisfy this condition.   Answer : 5, 10, 15
<result>C</result>
I brought 30 books on Mathematics, Physics, and Chemistry, priced at Rs.17, Rs.19, and Rs.23 per book respectively, for distribution among poor students of Standard X of a school. The physics books were more in number than the Mathematics books but less than the Chemistry books, the difference being more than one. The total cost amounted to Rs.620. How many books on Mathematics, Physics, and Chemistry could have been bought respectively?