Tough and Tricky questions: Word Problems.
It takes Sarah 20 minutes to do one oil change, and it takes Alice 12 minutes. If Sarah and Alice both begin doing oil changes at exactly 9:00 a.m. without pausing, when is the first time at which they will finish changing the oil of a car simultaneously?
Options: A) 10:00 a.m. B) 10:42 a.m. C) 12:00 a.m. D) 1:00 p.m. E) 2:00 p.m.
LCM of 1220   12 = 2 * 2 * 3   20 = 2 * 2 * 5   LCM = 2 * 2 * 3 * 5= 
<gadget id="calculator">2 * 2 * 3 * 5</gadget>
<output>60</output>
60= 1 hour   100010:00 a.m.M   10:00 a.m.
<result>A</result>
Tough and Tricky questions: Word Problems.
It takes Sarah 20 minutes to do one oil change, and it takes Alice 12 minutes. If Sarah and Alice both begin doing oil changes at exactly 9:00 a.m. without pausing, when is the first time at which they will finish changing the oil of a car simultaneously?