Let A be the event that the absolute difference between two randomly chosen real numbers in the sample space [0, 60] is less than or equal to a.If P(A)=1136, then a is equal to ______ . [2023]
(10)
|x-y|≤a
⇒ -a≤x-y≤a ⇒ x-y≤a and x-y≥-a
P(A)=ar(OACDEG)ar(OBDF)=ar(OBDF)-ar(∆ABC)-ar(∆EFG)ar(OBDF)
⇒ 1136=602-12(60-a)2-12(60-a)23600
⇒ 1100=3600-(60-a)2
⇒ (60-a)2=2500 ⇒ 60-a=50 ⇒ a=10