//Variable declaration
ni1=2.5*10**19;    //number of electron hole pairs
T1=300;     //temperature(K)
Eg1=0.72*1.6*10**-19;    //energy gap(J)
k=1.38*10**-23;     //boltzmann constant
T2=310;    //temperature(K)
Eg2=1.12*1.6*10**-19;    //energy gap(J)

//Calculation
x1=-Eg1/(2*k*T1);
y1=(T1**(3/2))*exp(x1);
x2=-Eg2/(2*k*T2);
y2=(T2**(3/2))*exp(x2);
ni=ni1*(y2/y1);          //number of electron hole pairs

//Result
printf('number of electron hole pairs is %0.3f    *10**16 per cubic metre    \n',(ni/10**16))
printf('answer varies due to ing off errors')