Quantitative Aptitude - Arithmetic Ability Questions

(3x + 2) (2x - 5) = ax2+kx+n ...............(1)

But (3x + 2)(2x - 5) = 6x2-11x-10........(2)

so by comparing (1) & (2),

we get a= 6, k= -11 , n= -10

(a - n + k) = 6 + 10 - 11 = 5.

Let the number X is 100

Then, PÃ 80 QÃ 72

So, Percentage decrease from P to Q is à 8/80=0.1-100=10%

1 is the right choice.

Sum of decimal places = 7.

Since the last digit to the extreme right will be zero (since 4 x 5 = 20), so there will be 6 significant digits to the right of the decimal point.

Given Karthik’s age = 32 years

Karthik’s son age = 7 years

Difference between their ages = K - S = 32 - 7 = 25 years ….(1)

Now, required K = 2S ……(2)

Put (2) in (1)

2S - S = 25

=> S = 25 years

Hence, at the age of 25 years of Karthik’s son, Karthik will be twice as his son’s age.

25 - 7 = 18 years

Therefore, after 18 years the father be twice as old as the son.

The total marks of all 5 subjects = 82 x 5 = 410

Total marks of 1st two subjects = 86.5 x 2 = 173

Total marks of last two subjects = 84 x 2 = 168

Now, marks in 3rd subject = 410 - (173 + 168) = 410 - 341 = 69.