Peter the optician sees 16 patients one Tuesday.4 are neither short nor long sighted,the total number of short sighted patients is 2 more than the total number of long sighted,how many patients can be short sighted, how many long sighted, and how many will require varifocal lenses

Solution:

Number of patients  having neither long nor shortsightedness = 4

Let number of patients having long sightedness be "x"

The total number of short sighted patients is 2 more than the total number of long sighted

Therefore,

Number of patient having shortsightedness = x + 2

Peter the optician sees 16 patients one Tuesday

Total number of patients = 16

Therefore,

x + x + 2 + 4 = 16

2x + 6 = 16

2x = 16 - 6

2x = 10

x = 5

Number of patients having longsightedness = x = 5

Number of patient having shortsightedness = x + 2 = 5 + 2 = 7

Patients requiring varifocal lenses will be = 5 + 7 = 12