Editorial Board Solutions for Chapter: Arithmetic Maths, Exercise 1: NUMBER SYSTEM

In a group of $40$ persons, $15$ drink tea but not coffee and $18$ drink coffee but not tea. If they drink at least one of the drinks, how many persons in the group drink tea?

A number when multiplied by $21$ is increased by $200$. Find the number.

The sum of the digits of a two-digit number is $11$. On adding $27$ to the given number, its digits are reversed. Find the number.

Find the remainder when ${25}^{25}$ is divided by $26$.

Find the least number at $*$ place when $517*324$ is divisible by $3$.

Find the least number at $*$ place when $97215*6$ is divisible by$11$.

What will come in place of question mark (?) in the given question?

$(1^2-2^2+3^2-4^2+5^2-6^2+..........9^2-{10}^2)=?$

Sum of the two numbers is $12$,  their product is $35$, What is the sum of the reciprocals of these numbers?