Rory collects rainwater. He has 100 L of rainwater in his tank. During a heavy rainstorm, water flows into the tank at a rate of 2 L/min for 90 minutes. How much water is in the tank at the end of the heavy rain?
During the heavy rain, the tank collects 2 * 90 = 
<gadget id="calculator">2*90</gadget>
<output>180</output>
180 L of water.
The tank has a total of 100 + 180 = 
<gadget id="calculator">100+180</gadget>
<output>280</output>
280 L of water.

<result>280</result>