Number System Easy Questions and Answers

Three fourth of one-fifth of a number is 60. The number is ?

Let the required number be N.
So 3/4 x 1/5 x N = 60

Let the required number be N.
So 3/4 x 1/5 x N = 60
⇒ 3N / 20 = 60
∴ N = 400

The difference between the squares of two consecutive number is 35. The number are ?

Let the two number be x and (x + 1)
Then, (x+1)² - x² = 35

Let the two number be x and (x + 1)
Then, (x+1)² - x² = 35
⇒ 2x = 34
⇒ x = 17
So, the number are 17 and 18

The ratio between two numbers is 3:4 and their sum is 420. The greater of two number is ?

Let the number be 3N and 4N.
Then, 3N + 4N = 420

Let the number be 3N and 4N.
Then, 3N + 4N = 420
⇒ 7N = 420
⇒ N = 60
∴ Greater number = 4 x 60 = 240

The sum of two number is 100 and their difference is 37. The difference of their squares is ?

Let the numbers be a and b.
Then, a + b = 100 and a - b = 37
∴ a² - b² = (a+b) (a-b)

Let the numbers be a and b.
Then, a + b = 100 and a - b = 37
∴ a² - b² = (a+b) (a-b)
= 100 x 37
= 3700

The difference of two number is 8 and 1/8th of their sum is 35. The number are ?

Let the number be x and (x + 8)
Then, 1/8[x + (x + 8)] = 35

Let the number be x and (x + 8)
Then, 1/8[x + (x + 8)] = 35
⇒ 2x + 8 = 280
⇒ 2x = 270
∴ x = 136
So, the number are 136 and 144.

Number System