Thin lens(urgent)

Two converging lenses having focal lengths of 30 mm and 40 mm. The two lenses are placed 20 mm apart. An object is placed 40 mm in front of the first lens. Determine the position of the image by:
a)lens formula
u1 = 40mm f1 = 30mm
(1/v1) = (1/f1) - (1/u1)
(1/v1) = (1/30) - (1/40)
v1 = 120mm
u2 = d – u1 = 20 – 120 = -100mm
f2 = 40mm
(1/v2) = (1/f2) - (1/u2)
(1/v2) = (1/40) - (-1/100)
v2 = 28.6mm



b) parallel-ray method
?????