clear
//Given
ug=1.5
R1=50.0                     //cm
R2=-50.0                   //cm
uw=9/8.0

//Calculation
f=1/((ug-1)*((1/R1)+(1/R1)))
f1=1/((uw-1)*((1/R1)+(1/R1)))

//Result
printf("\n (i) Focal length in air is %0.3f  cm", f)