The series of differences between consecutive prime numbers is represented as Cp1, Cp2, Cp3, .... Cpn , Whare Cp1 is the difference between the second and the first prime number. Find the sum of series when n = 23, given that the 23rd prime number is 83 ?

Correct Answer: 21

Explanation:

Total number of exams written by 100 students = 48 + 45 + 38 = 131
Now let us say x members are writing only 1 exam, y members are writing only 2 exams, z members are writing only 3 exams.
Therefore, x + 2y + 3z = 131 also x + y + z = 100.
Given that z = 5. So x + 2y = 116 and x + y = 95.
Solving we get y = 21.
So 21 members are writing exactly 2 exams.

Correct Answer: Rs. 2200

Explanation:

He sold 4 cycles for Rs. 8400
[It means each cycle price is Rs. 2100]
And again he sold 3 cycles for Rs. 1900 each
If he want to gain avg profit on each cycle is Rs. 320 per cycle.
So profit for 10 cycles is @ Rs.320 is,
10 x 320 = Rs. 3200
He already got Rs. 1850 profit by selling 7 cycles.
Now, remaining amount is 3200 - 1850 = 1350
So from remaining 3 cycles we want to get Rs. 1350 profit ,
1350/3 = 450
so he must sell remaining 3 cycles at Rs. 2200 each one.

Correct Answer: 29

Explanation:

Let the five consecutive odd numbers be x-4, x-2, x, x+2, x+4

According to the question,

Difference between square of the average of first two odd number and the of the average last

two odd numbers is 396

i.e, x+3 and x-3

$$\begin{gathered} ? x + 3 2 - x - 3 2 = 396 \\ ? x 2 + 9 + 6 x - x 2 + 6 x - 9 = 396 \\ ? 12 x = 396 \\ ? x = 33 \end{gathered}$$

 

Hence, the smallest odd number is 33 - 4 = 29.

Correct Answer: 64

Explanation:

7th stop only one was left and in each preceding stop twice the nos... there were so 6 stops before 7th.

 

so  2 6 = 64

Correct Answer: 200

Explanation:

As per given 

 

  40 100 × 250 = 50 100 × x

 

? x = 200

Correct Answer: 85

Explanation:

Since the numbers are co-prime, they contain only 1 as the common factor.
Also, the given two products have the middle number in common.
So, middle number = H.C.F of 551 and 1073 = 29;
First number = 551/29 = 19
Third number = 1073/29 = 37.
Required sum = 19 + 29 + 37 = 85.

Correct Answer: 2

Explanation:

A number is divisible by 9 only if the sum of the digits of the number is divisible by 9.

Here 86236 = 8 + 6 + 2 + 3 + 6 = 25

We must add 2 to 25 to become 27 which is divisible by 9.

Correct Answer: 210

Explanation:

Let the required number be 'p'

We know, sum of angles in a triangle are 180 deg

According to given data,

p - p/7 = 180

7p - p = 180 x 7

=> 6p = 1260

=> p = 1260/6 = 210

Correct Answer: 8

Explanation:

Let the required number be 'p'.

From the given data,

p + 12 = 160 x 1/p

=> p + 12 = 160/p

=> p(p + 12) = 160

=> P^2 + 12p - 160 = 0

=> p^2 + 20p - 8p - 160 = 0

=> P(p + 20) - 8(p + 20) = 0

=> (p + 20)(p - 8) = 0

=> p = -20 or p = 8

As, given the number is a natural number, so it can't be negative.

Hence, the required number p = 8.

Correct Answer: 216

Explanation:

Let the number be x.

 

Then, 2/3x-50 = 1/4x +50

 

=>  5/12x = 90

 

x = (90 x 12) / 5 = 216