High wbc count 15000. fever since 5 days. baby years 3. what problem sir ? what will be solution ?

I don't find the white count that unusual for that age. You give no differential that might be helpful. How much fever & pattern are not given. Without more specific information, a review of the history, exam and other lab data the cause and seriousness are undefined. You are welcome to start over. Solutions depend on an accurate assessment.

Agree that more information would be needed for specific advice and diagnosis. This white count is elevated for a child and with the fever, means there is some sort of infection, but with this information, can’t tell if viral or bacterial. So best to have the child examined by a doctor especially if not improving, to get proper diagnosis and advice.

Please describe the symptoms associated with the fever. A fever five days or more should be further investigated. This may include testing for Flu, COVID 19 , CRP and a urinalysis. Watch for signs of rash, swelling, eye redness since these signs are associated with Kawasaki disease. Keep your child well hydrated, monitor temperature and breathing.