The image formed is 0.25 times the size of the object and 10 cm behind the pinhole. If the height of image on screen is 6 cm what is the distance of the object from the screen?

40 cm

Explanation:

Magnification of a pinhole camera is given by;

M= height of image/ height of object

Since;

M= 0.25

Height of image = 6cm

Height of object = height of image / M

Height of object = 6/0.25 = 24 cm

Height of image/ height of object = distance of image from pinhole/ distance of object from pinhole

Since the distance of image from pinhole = 10cm

Let the distance of object from pinhole be x

6/24 = 10/x

6x = 240

x= 240/6

x = 40 cm

the total distance traveled by the car is

30km + 49km = 79 km .