Question

If the person can't accommodate and the glasses is + 2.50d, at which distance will the person see clearly

Answer 1

At 2/5 of a Meter is where the person can see clearly.

At a + diopter measurement is a nearsighted person take the value of 2.5 and make it the denominator with 1 as the numerator to find the distance in meters that they can see clearly past their face.
1/2.5 = 2/5 of a meter.

Answer 2

40 cm or 2/5 of a meter.

Explanation:

A short-sighted person, at a positive diopter, will take an estimation of about 2.5 and make it the denominator by 1 as the numerator to find out the distance (in meters) that they can see clearly.

We can find the value of f, given the value for P:

P = +2.50

f = 1 / p = 1 / 2.50

(changing the units, it will be) ---> 100 / 2.50 which is equal to 40 cm.

Therefore, 40 cm which is 2/5 of a meter is the distance a person with glasses +2.5d can see clearly.