Multiples of 11 whose square
root are whole number
First = 11 × 11 = 121
Second = 11 × 11 × 4 = 484

Correct Option: A

Multiples of 11 whose square
root are whole number
First = 11 × 11 = 121
Second = 11 × 11 × 4 = 484

Let the number be x. Then,
x² = (75.15)² – (60.12)²
= (75.15 + 60.12) (75.15 – 60.12)
= 135.27 × 15.03
= 2033.1081
⇒  x = √2033.1081
= 45.09

Correct Option: C

Let the number be x. Then,
x² = (75.15)² – (60.12)²
= (75.15 + 60.12) (75.15 – 60.12)
= 135.27 × 15.03
= 2033.1081
⇒  x = √2033.1081
= 45.09

Let the required number be x. Then,
x² + 5² = 386
⇒  x² = 386 – 25
⇒  x² = 361
⇒  x = √361 =19

Correct Option: B

Let the required number be x. Then,
x² + 5² = 386
⇒  x² = 386 – 25
⇒  x² = 361
⇒  x = √361 =19

Let the required number be x.
As per given information,
x² = (975)² – (585)²
⇒  x² = (975 + 585) (975 – 585)
⇒  x² = 1560 × 390
⇒  x = √1560 × 390
= √13 × 12 × 3 × 13 × 10 × 10
= 780

Correct Option: A

Let the required number be x.
As per given information,
x² = (975)² – (585)²
⇒  x² = (975 + 585) (975 – 585)
⇒  x² = 1560 × 390
⇒  x = √1560 × 390
= √13 × 12 × 3 × 13 × 10 × 10
= 780

Let x + y = 20 and
x – y = 8
∴  (x + y) (x – y) = 20 × 8
⇒  x² – y² = 160

Correct Option: D

Let x + y = 20 and
x – y = 8
∴  (x + y) (x – y) = 20 × 8
⇒  x² – y² = 160