Question

The number of numbers lying between 100 and 500 that are divisible by 7 but not by 21 is-

• A. 19
• B. 38
• C. 57
• D. 76

Answer 1

Answer: (B)

38

Answer 2

The numbers which are divisible by 7 and lying between 100 & 500 are 105, 114, 121,...., 497.

then total numbers are = $\frac { 497 - 105 } { 7 }$ + 1 = 57

and the numbers which are divisible by 21 are

105, 126, 147, …., ….., …., 483

Then total numbers are = $\frac { 483 - 105 } { 21 }$ + 1 = 19

So required number = 57 – 19 = 38