Number System
-  A number whose fifth part increased by 5 is equal to its fourth part diminished by 5 is ?
- 
                        View Hint View Answer Discuss in Forum Let the number be N. 
 Then, (N/5) + 5 = (N/4) - 5Correct Option: CLet the number be N. 
 Then, (N/5) + 5 = (N/4) - 5
 ⇒ (N/4) - (N/5) = 10
 ⇒ (5N - 4N)/20 = 10
 ∴ N = 200
-  The product of two numbers is 120. The sum of their squares is 289. The sum of the two numbers is ?
- 
                        View Hint View Answer Discuss in Forum Let the number be a and b . 
 Then, (a+b)2 = a2 + b2 + 2ab
 = 289 + 2 x 120
 = 289 + 240
 = 529
 ∴ a+b = √529 = 23Correct Option: BLet the number be a and b . 
 Then, (a+b)2 = a2 + b2 + 2ab
 = 289 + 2 x 120
 = 289 + 240
 = 529
 ∴ a+b = √529 = 23
-  The sum of squares of two numbers is 80 and the square of their difference is 36. The product of the two numbers is ?
- 
                        View Hint View Answer Discuss in Forum Let the number be a and b. 
 Then, a2 + b2 = 80
 and (a-b)2= 36
 Correct Option: ALet the number be a and b. 
 Then, a2 + b2 = 80
 and (a - b)2= 36
 ⇒ a2 + b2 - 2ab = 36
 ⇒ 2ab = (a2 + b2)-36
 = 80 - 36= 44
 ∴ Product = ab = 22
-  The sum of two number is twice their difference, If one of the number is 10, the other number is ?
- 
                        View Hint View Answer Discuss in Forum Let the other number be x. 
 Then, 10 + x = 2(x - 10)Correct Option: BLet the other number be x. 
 Then, 10 + x = 2(x - 10)
 ⇒ x = 30
-  4/5 of a certain number is 64, Half of that number is ?
- 
                        View Hint View Answer Discuss in Forum Let the number be N, 
 Then 4N/5 = 64
 ⇒ N = 64 x 5/4 = 80Correct Option: BLet the number be N, 
 Then 4N/5 = 64
 ⇒ N = 64 x 5/4 = 80
 ∴ Half of the number = 80/2 = 40
 
	