ISBtarget wrote:

If the successive tick marks shown on the number

line above are equally spaced and if x and y are the

numbers designating the end points of intervals as

shown, what is the value of y ?

(1) x =

1

2

(2) y – x =

2

3

Arithmetic Properties of numbers

(1) If 3 tick marks represent a value of

1

2

, then

6 tick marks would represent a value of 1.

From this it can be established that each

subdivision of the line represents

1

6

, so the

value of y is

7

6

; SUFFICIENT.

From where did they get the information that 3 tick mark represents 1/2, why cant it represent 1/4 or even 1

Imagine 2 endpoints at x = 2 and y = 4...and there is one tickmark in between, let's call it z

that would mean 1/2 of x + y

same with the distance between 0 and 1 one tickmark in between is 1/2

one tickmark in between two numbers can't be 1/4 per tickmark