PareshGmat wrote:

How many multiples of 7 are there between 21 and 343, exclusive ?

A. 48

B. 47

C. 46

D. 45

E. 44

ASIDE: there are various formulas that students can memorize for this kind of question. Here's a solution that uses a nice easy rule (which can be applied in many ways):

The number of integers from x to y inclusive equals y - x + 1exclusive: so, we're not going to count 21 and 343

The multiples of 7 to be counted are:

28

35

42

.

.

.

336

We can REWRITE the values as follows:

28 = (

7)(

4)

35 = (

7)(

5)

42 = (

7)(

6)

.

.

.

336 = (

7)(

48)

So, we need only find the number of integers from

4 to

48 inclusive

Applying the above

rule, the number of integers =

48 -

4 + 1 =

45Answer: D

Cheers,

Brent

_________________

Brent Hanneson – Founder of gmatprepnow.com