yup it is 225
no. of ways p and q has r as a factor giving r2 as LCM
p having no r as factor
q having r2 as factor
p---->r
q----->r2
p----->r2
q----->r
p------>r2
q----->r
p------>r2
q----->r2
total 5 ways
simillarly for s we have 5 ways
for t
p q
no t t4
t t4
t2 t4
t3 t4
t4 t0,t,t2,t3t4
9 ways
total 5*5*9=225