A certain hobby shop sold model cars for $5.00 each and model trains for $8.00 each. If a customer purchased both cars and trains from the store for a total of $31.00, what total number of cars and trains did the customer purchase?  Options.
A) 3  B) 4  C) 5  D) 6  E) 7
we can take numbers, as price of car 5, 8 for train and 31 total for ease.   Now we can determine quickly that total number should range between 31/8 &lt;= N &lt;=31/5 , so ans should be between 3 and 7.   Now solving the expression 5A+8B =31   decreasing 31 in multiple of 5 and checking divisibility of that number by 8. this way we get   3 cars, 2 trains we get $31.00 total  3*5 + 2*8= 
<gadget id="calculator"> 3*5 + 2*8</gadget>
<output>31</output>
31   Hence total number is  3 + 2= 
<gadget id="calculator"> 3 + 2</gadget>
<output>5</output>
5   Ans 5
<result>C</result>
A certain hobby shop sold model cars for $5.00 each and model trains for $8.00 each. If a customer purchased both cars and trains from the store for a total of $31.00, what total number of cars and trains did the customer purchase?