Andy is running late. School starts at 8:00 AM and it normally takes him 30 minutes to get there, but today he had to stop for 3 minutes each at 4 red lights and wait 10 minutes to get past construction. If he left his house at 7:15, how many minutes late will he be?
First find how many minute Andy had to get to school when he left his house: 8:00 AM - 7:15 AM = 45 minutes.
Then find the total time he spent waiting at red lights: 3 minutes/light * 4 lights = 
<gadget id="calculator">3*4</gadget>
<output>12</output>
12 minutes.
Now add the normal travel time, red light time, and construction wait time to find Andy's total travel time: 30 minutes + 12 minutes + 10 minutes = 
<gadget id="calculator">30+12+10</gadget>
<output>52</output>
52 minutes.
Now subtract the amount of time Andy had when he left his house from that number to find how many minute late he is: 52 minutes - 45 minutes = 
<gadget id="calculator">52-45</gadget>
<output>7</output>
7 minutes.

<result>7</result>