TCS Ninja Equations Questions and Answers Part 1

Let x ques were correct. Therefore, (26- x) were wrong
8x−5(26−x)=08x−5(26−x)=0
Solving we get x=10

Video solution:

The primes p such that 3 < p < 100 and of the form 4x+1 are 5, 13, 17, 29, 37, 41, 53, 61, 73, 89 and 97. These are eleven in number.

Lets assume younger age = x Years.
So, elder age will be (as per question) = (x+25) years.
Given:
(X+25)-9 = 6(X-9)
By Solving the above equation
=>  x=14 which is the age of younger
elder = 25+14 = 39 years.

sum of their current ages = 39+14 = 53

Video solution:

Let three consecutive odd integeres be
x,x+2,x+4
4x=6+2(x+4)
x=7
x+4=11

Ans= 25

Let the two digit number be 10x+y
Adding 2 after doubling the number is reverse of the number.
So 2(10x+y)+2 = 10y+x
19x -8y +2=0
Above equation satisfies for the value, x=2, y=5
So the number is 10*2+5= 25

Video solution:

Step-by-step explanation:

43 ( 10 x + y ) = 34 ( 10 y + x )

430 x + 43 y = 340 y + 34 x

430 x - 34 x = 340 y - 43 y

396 x = 297 y

We also know that : x + y = 14

y = 14 - x

396 x = 297 ( 14 - x )

396 x = 4158 - 297 x

693 x = 4158

x = 4158 : 693, x = 6

y = 14 - 6 = 8

Prove: 43 * 68 = 34 * 86

2924 = 2924

Therefore this number is 68 (the reverse is 86).

19x + 19y + 17 = -19x + 19y - 21
38x = -38 => x = -1

2C + 3T = 1300 --- (1)
3C + 3T = 1200 --- (2)
Subtracting 2nd from 1st, we get
-C + T = 100 => T - C = 100

Let the numerator and denominator of the fraction be 'n' and 'd' respectively.
d = 2n - 1
(n + 1)/(d + 1) = 3/5
5n + 5 = 3d + 3
5n + 5 = 3(2n - 1) + 3 => n = 5
d = 2n - 1 => d = 9
Hence the fraction is : 5/9.

Let the costs of each kg of apples and each kg of rice be Rs.a and Rs.r respectively.
10a = 24r and 6 * 20.50 = 2r
a = 12/5 r and r = 61.5
a = 147.6
Required total cost = 4 * 147.6 + 3 * 61.5 + 5 * 20.5
= 590.4 + 184.5 + 102.5 = Rs.877.40