Question

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The number of positive integers less than 1849 and prime to 43 is :
a) 1806
b) 1723
c) 1541
d) 1324

Answer 1

This the set of +ve integers that are less than 1849 and not divisible by number 43. 

1849 / 43 = 43. Thus number of +ve integers = 1849 - 43 = 1806...... hope it may help you ....#MB

Answer 2

Hey friend, Harish here.

Here is your answer:

Total no. Of positive integers till 1849 = 1849.

No of multiples of 43 between 1 to 1849 = $\frac{1849}{43}=43$

Then,

As 43 is a prime number is doesn't have any other factors.

So,

Total number of number less than 1849 & co -prime to 43 are:

1849 - 43 = 1806.

Therefore 1806 is the answer. (OPTION A)
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Hope my answer is helpful to you.