# Average Questions

FACTS  AND  FORMULAE  FOR  AVERAGE QUESTIONS

1. Average =$\inline \fn_cm \left ( \frac{Sum \; of\; observations}{No.of\; observations} \right )$

2. Suppose a man covers a certain distance x kmph and an equal distance at y kmph. Then, the average speed during the whole journey is$\inline \fn_cm \left ( \frac{2xy}{x+y} \right )$Kmph

Q:

A batsman makes a score of 87 runs in the 17th inning and thus increases his average by 3. Find his average after 17th inning?

Let the average after 7th inning = x

Then average after 16th inning = x - 3

$\inline&space;\fn_jvn&space;\therefore$ 16(x-3)+87 = 17x

$\inline&space;\fn_jvn&space;\therefore$  x = 87 - 48 = 39

19737
Q:

The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero ?

 A) 0 B) -1 C) 1 D) none of these

Explanation:

Average of 20 numbers = 0.

$\inline \fn_cm \therefore$Sum of 20 numbers = (0 * 20) = 0.

It is quite possible that 19 of these numbers may be positive and if their sum is a, then 20th number is (- a).

75 19041
Q:

The average of runs of a cricket player of 10 innings was 32. How many runs must he make in his next innings so as to increase his average of runs by 4 ?

 A) 76 B) 79 C) 85 D) 87

Explanation:

Average = total runs / no.of innings = 32

So, total = Average x no.of innings = 32 x 10 = 320.

Now increase in avg = 4runs. So, new avg = 32+4 = 36runs

Total runs = new avg x new no. of innings = 36 x 11 = 396

Runs made in the 11th inning = 396 - 320 = 76

32 18266
Q:

The average weight of 8 persons increases by 2.5 kg when a new person comes in place of one of them weighing 65 kg. What might be the weight of the new person ?

 A) 70 kg B) 75 kg C) 80 kg D) 85 kg

Explanation:

Total weight increased = (8 x 2.5) kg = 20 kg.

Weight of new person = (65 + 20) kg = 85 kg.

39 18161
Q:

A grocer has a sale of Rs 6435, Rs. 6927, Rs. 6855, Rs. 7230 and Rs. 6562 for 5 consecutive months. How much sale must he have in the sixth month so that he gets an average sale of Rs, 6500 ?

 A) 4991 B) 5467 C) 5987 D) 6453

Explanation:

Total sale for 5 months = Rs. (6435 + 6927 + 6855 + 7230 + 6562) = Rs. 34009.

$\inline \fn_jvn \therefore$Required sale = Rs.[(6500 x 6) - 34009]

= Rs. (39000 - 34009)

= Rs.  4991.