Question

How many numbers between 70 and 300 are divisible by either 2 or 3 but not both?​

Answer 1

Answer:

Step-by-step explanation:

well, for knowing whether a number is divisible by 3 or not there is a trick.

for that, you need to add all the digits of a given number and if the resultant number is

the multiple of 3, then the whole number is divisible by 3.(then and only then)

for example,the no. is 2382…thus we check…2+3+8+2=15.here, 15 is divisible by 3 thus the whole number 2382 is divisible by 3. (2382/3=794).

and for 5 , only the numbers ending with 0 and 5 are divisible by 5.(this is called divisibility test)……..keeping this in mind, there are many numbers divisible between one and 300 …….but this would be a long method to count….thus , we can see here that 3*100 =300 and 3*1=3 .thus, 98 numbers lie in between 1 and 300(excluding both of 1 and 300) which are divisible by 3. same way, 5*1=5 and 5*60=300……thus 58 numbers lie in between 1 and 300 divisible by 5.

thus, the total numbers divisible by at least 5 and 3 are 58+98–1=155 (this “-1” is because 15 is the common multiple of 3 and 5).