Answer 1

Given:
F length, f = 18 cm
I distance,v = 24 cm
Png these values in lens formula, we get:
1- 1/u = 1/f
o/u = 1/v-1/f
o1/u = 1/24-1/18 =-(1/72)
o =-72 cm
T the object should be placed at a distance of 72 cm from the lens.
N
Mfication, m = v /u = 24/ (-72) =-(1/3)