Physics
posted by Xander .
How far from a converging lens with a focal length of 15 cm should an object be placed to produce a real image which is half the size of the object?
How do you solve this?
Thanks!

M = 1/2 =  di/do
di = 1/2 do
then
1/15 = 1/(0.5 do) + 1/do = 3/do
do/3 = 15/1
do = 45 cm
Old Science Guy gave you this.