In a mixture of three varities of oils , the ratio of their weight is 4 : 5 : 8. If 5 kg of oils of the first variety, 10 kg of the second variety and some quantity of oils of the third variety are added to the mixture, the ratio of the weights of three varieties of oils becomes as 5 : 7 : 9 in the final mixture, find the quantity of third variety of oil was ?

Correct Answer: 15 years

Explanation:

Let avg ages of 5 members at present is G

And age of new member is m and an older is n

Required = (5G + m - n)/5 = G - 3

m - n = 15 years

Correct Answer: 2

Correct Answer: 3600

Explanation:

Manager's monthly salary Rs. (1600 * 21 - 1500 * 20) = Rs. 3600.

Correct Answer: 120

Explanation:

Let the three numbers be x, y, z.

From the gien data,

x = 2y ....(1)

x = z/2 => z = 2(2y) = 4y .....(From 1)  ...........(2)

Given average of three numbers = 56

Then,

 

$$\begin{gathered} x + y + z 3 = 56 \\ 2 y + y + 4 y 3 = 56 ( From 1 & 2 ) \\ 7 y = 56 x 3 \\ y = 24 \end{gathered}$$

Now,

x = 2y => x = 2 x 24 = 48

z = 4y = 4 x 24 = 96

 

Now, the highest number is z = 96 & smallest number is y = 24

 

Hence, required sum of highest number and smallest number

= z + y

= 96 + 24

= 120.

Correct Answer: 84 km/hr

Explanation:

Let the speeds of the car, train and bus be 5x, 9x and 4x km/hr respectively.
Average speed = 5x + 9x + 4x/3 = 18x /3 = 6x km/hr.
Also, 6x = 72 => x = 12 km/hr
Therefore, the average speed of the car and train together is = 5 x + 9 x 2= 7x = 7 x 12 = 84 km/hr.

Correct Answer: Rs. 3944

Explanation:

Let the side of the square plot be 'a' ft.
Given area of the plot (a x a) = 289 => a = 17
Length of the fence = Perimeter of the plot = 4a = 68 ft.
Cost of building the fence = 68 x 58 = Rs. 3944.

Correct Answer: 1000(p - q) + qr

Explanation:

We need to find the total cost to send r messsages, r > 1000.

The first 1000 messsages will cost Rs.p each (Or) 

The total cost of first 1000 messsages = Rs.1000p

The remaining (r - 1000) messsages will cost Rs.q each (Or)

The cost of the (r - 1000) = Rs.(r - 1000)y

 

Therefore, total cost = 1000p + rq - 1000q

= 1000(p - q) + qr

Correct Answer: 81.5

Explanation:

Let the number of students in classes A, B and C be P, Q and R respectively.
Then, total score of A = 83P, total score of B = 76Q, total score of C = 85R.
Also given that,
(83P + 76Q) / (P + Q) = 79
=>4P = 3Q.
(76Q + 85R)/(Q + R) = 81
=>4R = 5Q,
=>Q = 4P/3 and R = 5P/3
Therefore, average score of A, B, C = ( 83P + 76Q + 85R ) / (P + Q + R) = 978/12 = 81.5

Correct Answer: 192

Explanation:

Let the third subject marks be 'x'
=> Second subject marks = 2x
=> Third subject marks = 4x
Given avg = 224
x + 2x + 4x = 224 x 3
=> 7x = 224 x 3
=> x = 96
Hence, Second subject marks = 2x = 2 x 96 = 192.

Correct Answer: 4

Explanation:

Given that, 

Number of windows = 50

Each window covering covers 15 windows

=> 50 windows requires 50/15 window coverings

= 50/15 = 3.333

 

Hence, more than 3 window coverings are required. In the options 4 is more than 3. 

 

Hence, 4 window coverings are required to cover 50 windows of each covering covers 15 windows.