If we assume all thirty 4-wheel drive cars in the parking lot have their spare tire with them, how many tires are in the parking lot?
Each car has 4 tires + 1 spare = 
<gadget id="calculator">4+1</gadget>
<output>5</output>
5 tires.
If there are 30 cars in the parking lot and each one has 5 tires, then the total number of tires is 30 * 5 = 
<gadget id="calculator">30*5</gadget>
<output>150</output>
150 tires.

<result>150</result>