Quantitative Aptitude - Arithmetic Ability Questions

a/(a + b) = 15/21 → a = 15, a + b = 21

→ b = 21– 15 = 6
⇒ a – b =15 – 6 = 9
⇒ (a + b)/(a – b) = 21/9

Total weight of 50 boys = 45 X 50 = 2250

Average weight of 49 boys = 44.9

Total weight of 49 boys = 44.9 X 49 = 2200.1

Weight of boy who left the class=2250–2200.1=49.9

Given that x = 2+ 223 + 213

So x - 2 = 223 + 213

Now cubing on both sides, we get

=> x3-8-6x2+12x = 4 + 2 + 6(x-2)

Therefore, x3-6x2+6x = -6 + 8 = 2

We know, the perimeter of a triangle = sum of all the sides of a triangle = a + b + c

Here given that sides a = 38, b= 36 and c = 18

Now, perimeter of the triangle = a + b + c = 38 + 36 + 18 = 92 units.

3/8 as a Decimal :

In this we should convert the denominator into 10, 100, 1000, 10000, 100000,... to make it simple.

Now to make 8 into 1000, we multiply numerator and denominator with 125

=> 3 x 1258 x 125 = 3751000 = 0.375

1/10 as a Decimal :

1 divided into 10 parts of each 0.1.

Therefore, 3/8 = 0.375 and 1/10 = 0.1 in decimals.

Let present age of Pranay = 15p

That of Sai = 17p

ATQ,

15p + 6/17p + 6 = 9/10

=> 150p + 60 = 153p + 54

=> p = 2

Therefore, Age of Pranay after 6 yrs = 15 x 2 + 6 = 36 years.