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61. The sum of the numerator and denominator of a fraction is 11. If 1 is added to the numerator and 2 is subtracted from the denominator, it becomes 23. The fraction is :

Discuss
Solution:
Let the fraction be xy
Then,
x+y=11.....(i)x+1y2=233(x+1)=2(y2)3x2y=7.....(ii)
Solving (i) and (ii), we get:
x = 3 and y = 8
So, the fraction is 38
62. In a Mathematics examination the number scored by 5 candidates are 5 successive odd integers. If their total marks are 185, the highest score is :

Discuss
Solution:
Let the five successive odd number be,
x, x + 2, x + 4, x + 6, x + 8
Then, according to given information,
185 = x + x + 2 + x + 4 + x + 6 + x + 8
185=5x+205x=185205x=165x=33
Highest number = 33 + 8 = 41
63. Three numbers are in in the ratio of 3 : 4 : 6 and their product is 1944. The largest of these numbers is :

Discuss
Solution:
Let the numbers be 3x, 4x and 6x
Then,
3x×4x×6x=194472x3=1944x3=27x=3
∴ Largest number = 6x = 18
64. The sum of the squares of two numbers is 3341 and the difference of their squares is 891. The numbers are :

Discuss
Solution:
Let the numbers be x and y.
Then,
x2 + y2 = 3341..... (i)
And,
x2 - y2 = 891..... (ii)
Adding (i) and (ii), we get :
2x2 = 4232
or x2 = 2116
or x = 46
Subtracting (ii) from (i), we get :
2y2 = 2450
or y2 = 1225
or y = 35
So, the numbers are 35 and 46
65. In a two-digit number, if it is known that its unit's digits exceeds its ten's digit by 2 and that the product of the given number and the sum of its digits is equal to 144, then the number is :

Discuss
Solution:
Let the ten's digit be x
Then, unit's digit = x + 2
∴ Number :
= 10x + (x + 2)
= 11x + 2
Sum of digits :
= x + (x + 2)
= 2x + 2
(11x+2)(2x+2)=14422x2+26x140=011x2+13x70=0(x2)(11x+35)=0x=2
Hence, required number:
= 11x + 2
= 11× 2 + 2
= 24
66. The difference between the numerator and the denominator of a fraction is 5. If 5 is added to its denominator, the fraction is decreased by 114. Find the value of the fraction.

Discuss
Solution:
Let the denominator be x
Then, numerator = x + 5
Now,
x+5xx+5x+5=54x+5x=54+1x+5x=94x+5x=214
So, the fraction is 214
67. A number whose fifth part increased by 4 is equal to its fourth part diminished by 10, is :

Discuss
Solution:
Let the number be x
Then,
(15x+4)=(14x10)x20=14x=14×20x=280
68. The ratio between a two-digit number and the sum of the digits of that number is 4 : 1. If the digit in the unit's place is 3 more than the digit in the ten's place, then the number is ?

Discuss
Solution:
Let the ten's digit be x
Then, units digit = x + 3
Number = 10x + (x + 3)
              = 11x + 3
Sum of digits = x + (x + 3)
                      = 2x + 3
11x+32x+3=4111x+3=8x+123x=9x=3
Hence, Required number
= 11x + 3
= 11 × 3 + 3
= 36
69. The difference between two positive integers is 3. If the sum of their squares is 369, then the sum of the numbers is :

Discuss
Solution:
Let the numbers be x and (x + 3)
Then,
x2+(x+3)2=369x2+x2+9+6x=3692x2+6x360=0x2+3x180=0(x+15)(x12)=0x=12
So, the numbers are 12 and 15
∴ Required sum = (12 + 15) = 27
70. A number consists of two digits. If the digits interchange place and the new number is added to the original number, then the resulting number will be divisible by :

Discuss
Solution:
Let the ten's digit be x and unit's digit be y
Then, number = 10x + y
Number obtained by interchanging the digits = 10y + x
∴ (10x + y) + (10y + x)
= 11(x + y), which is divisible by 11