Problems on Numbers with Explanation

Q1. The difference between a number and its four-fifth is 20. Find the number?

Answer- Option A

Explanation-

Let the number be x
According to the question, x -

4 5

x = 20

=> x = 100

Q2. Three numbers are added in pairs, the sum so obtained are 20, 27, and 23. What are those three numbers?

Q3. If the sum of two numbers is 40 and their product is 300. Find those two numbers?

Q4. A number is trebled, and 10 is added. If the resultant is doubled, we get 56. What is that number?

Q5. On multiplying the number by 6 and taking away 7 from the product produces the same result as tripling a number and adding 2 to the result. Find that number?

Q6. There is a two-digit number such that when 18 is subtracted to the number, the digits are reversed. Also, the product of its digits is 8. The number is

Answer- Option B

Explanation-

Let ten's and unit's digit be x and

8 x

=> 10x +

8 x

- 18 = 10

8 x

+ x

=> x = 4
Hence, the number is 42.

Q7. The product of two numbers is 3375. When the larger number is divided by the smaller, quotient obtained is 15. Determine the sum of the numbers?

Answer- Option A

Explanation-

Let the larger number be x and smaller number be y
According to the question, xy = 3375 and

x y

= 15

On solving these two equation, we obtain x=225 and y=15
So, the sum of the numbers is 240