A60 year old person has a threshold of hearing of 95.0 db for a sound with frequency f=10,000 hz. by what factor must the intensity of a sound wave of that frequency, audible to a typical young adult, (sound level=43.0 db) be increased so that it is heard by the older person.

if you know the sound level in db, then you can compute the sound intensity and take the ratio.

hint*
in the problem, they gave the intensity as decibels but want to know by what factor to increase the intensity (i) for the young person to get a sound that the older person can hear.

ignore f completely.

decibels (db) need to be converted to i using this equation:
i=(10^(db/10))*10^-12
do this for each db and divide the older person's db by the younger's.