An eye specialist prescribes spectacles having a combination of a convex lens of focal length 40cm in contact with a concave lens of focal length 25cm. The power of this lens combination is

An eye specialist prescribes spectacles having a combination of a conv

1.	An eye specialist prescribes spectacles having a combination of a convex lens of focal length 40cm in contact with a concave lens of focal length 25cm. The power of this lens combination is
Answer» `+1.5D` `-1.5D` `+6.67D` `-6.67D` ANSWER :B