Number System
-  A man engaged a servant on the condition that he would pay him ₹ 90 and a turban after service of one year. He served only for nine months and received the turban and an amount of ₹ 65. The price of turban is
- 
                        View Hint View Answer Discuss in Forum 12 months’ salary = ₹ 90 + turban 
 ∴ 9 months’ salary= (₹ 90 + turban) × 9 12 = ₹ 90 × 3 + 3 turban 4 4 = ₹ 135 + 3 turban 2 4 ∴ ₹ 135 + 3 turban 2 4 
 = ₹ 65 + turban∴ 1 turban = 135 − 65 = ₹ 5 4 2 2 ∴ Turban ⇒ 5 × 4 = ₹ 10 2 Correct Option: C12 months’ salary = ₹ 90 + turban 
 ∴ 9 months’ salary= (₹ 90 + turban) × 9 12 = ₹ 90 × 3 + 3 turban 4 4 = ₹ 135 + 3 turban 2 4 ∴ ₹ 135 + 3 turban 2 4 
 = ₹ 65 + turban∴ 1 turban = 135 − 65 = ₹ 5 4 2 2 ∴ Turban ⇒ 5 × 4 = ₹ 10 2 
-  If the operation ‘ * ’ is defined by a * b = a + b – ab, then 5 * 7 equals
- 
                        View Hint View Answer Discuss in Forum ∵ a * b = a + b – ab 
 ∴ 5 * 7 = 5 + 7 – 5 × 7 = 12 – 35
 = – 23Correct Option: C∵ a * b = a + b – ab 
 ∴ 5 * 7 = 5 + 7 – 5 × 7 = 12 – 35
 = – 23
-  A number is doubled and 9 is added. If the resultant is trebled, it becomes 75. What is that number ?
- 
                        View Hint View Answer Discuss in Forum Suppose number is x. 
 ∴ 3 (2x + 9) = 75
 ⇒ 6x + 27 = 75
 ⇒ 6x = 48 ⇒ x = 8Correct Option: CSuppose number is x. 
 ∴ 3 (2x + 9) = 75
 ⇒ 6x + 27 = 75
 ⇒ 6x = 48 ⇒ x = 8
-  The sum of two number is 8 and their product is 15. The sum of their reciprocals is
- 
                        View Hint View Answer Discuss in Forum If the numbers be x and y, 
 then
 x + y = 8 ....... (i)
 xy = 15 ...... (ii)
 Dividing equation (i) by (ii)x + y = 8 ⇒ x + y = 8 xy 15 xy xy 15 1 + 1 = 8 y x 15 Correct Option: AIf the numbers be x and y, 
 then
 x + y = 8 ....... (i)
 xy = 15 ...... (ii)
 Dividing equation (i) by (ii)x + y = 8 ⇒ x + y = 8 xy 15 xy xy 15 1 + 1 = 8 y x 15 
-  In a division sum, the divisor is 12 times the quotient and 5 times the remainder. If the remainder is 36, then the dividend is
- 
                        View Hint View Answer Discuss in Forum Divisor = 5 × remainder 
 = 5 × 36 = 180
 Again, Divisor = 12 × quotient
 ∴ 180 = 12 × quotient∴ Quotient = 180 = 15 12 
 ∴ Dividend = Divisor × Quotient + Remainder
 = 180 × 15 + 36
 = 2700 + 36 = 2736Correct Option: CDivisor = 5 × remainder 
 = 5 × 36 = 180
 Again, Divisor = 12 × quotient
 ∴ 180 = 12 × quotient∴ Quotient = 180 = 15 12 
 ∴ Dividend = Divisor × Quotient + Remainder
 = 180 × 15 + 36
 = 2700 + 36 = 2736
 
	