Quantitative aptitude

Durga prasad (Student CA CPT ) (116 Points)

08 June 2013  
plz explain it......
 
If a c oin is t ossed twice we g et, Rs 5 i f two
heads appear, Rs 2 if one head appear, Rs 1 if
no head appear. Then the expected income is
a) 3.5 b) 2.5 c) 4 .5 d) 5.5