Average MCQs Math

Q171: If the average of m numbers is n2 and that of n numbers is m2 , then the average of (m + n) numbers is?

m - n

m + n

m/n

mn

Q172: In a flight of 600 kms, an aircraft was slowed down due to bad weather and the average speed was reduced by 200 km/hour, and the time of flight increased by 30 minutes. What is the total duration of flight?

1 hour

2 hours

3 hours

4 hours

Explanation

Equation Setup:

In bad weather: $600 = (v - 200)(t + 0.5)$
In good weather:
$600 = v t$
Solving for $v$
$v = 600/t$

Substituting $v$ in the first equation:

600 = left(frac{600}{t} - 200right)(t + 0.5)

Expanding and simplifying the equation:

$600t = 600t + 300 - 200^2 - 100t$ $-200t^2 - 100t + 300 = 0$ $2t^2 + t - 3 = 0$

Solving the quadratic equation:

$2t^2 + 3t - 2t - 3 = 0$ $2t(t - 1) + 3(t - 1) = 0$ $(2t + 3)(t - 1) = 0$

Finding values for $t$ :

$2t + 3 = 0 quad text{or} quad t - 1 = 0$ $2 t = - 3 \Rightarrow t = - \frac{3}{2} (negative, not possible)$ $t = 1 quad text{(valid answer)}$

Q173: if the price of a carpet 8 meters long and 3 meters wide is Rs.6288, what will be the price of 12 meters long and 6-meter wide carpet?

اگر 8 میٹر لمبے اور 3 میٹر چوڑے قالین کی قیمت 6288 روپے ہے تو 12 میٹر لمبے اور 6 میٹر چوڑے قالین کی قیمت کیا ہوگی؟

17647

82721

62731

18864

Q174: The average of three numbers is 20. If two numbers are 16 and 22, the third is?

18

20

22

19

Q175: A class had 14 boys with an average height of 5.3 feet. A new boy joined the class. Now the average of the 15 boys in the class was 5.25 feet. How tall was the new boy?

4.55 feet

5.55 feet

3.55

None of these

Q176: Nasir read 60 pages of a book on the first day. This was 20% more than the number of pages he read on the second day. Given that he read 1/6 of the book on the second day, find the number of pages in the book he had read.

300

290

325

345

Explanation

Step 1: Define Variables

Let the number of pages Nasir reads on the second day be x.

We are given that on the first day, he read 60 pages, which was 20% more than what he read on the second day.

So, we can set up the equation:

$60 = x + \frac{20}{100} \times x$ $60 = x + 0.2x$ $60 = 1.2 x$ $x = 60/$ 1.2=50

Step 2: Find Total Pages in the Book

It is also given that on the second day, he read $frac{1}{6}$ of the book, meaning:

$50 = 1/6 \times Total Pages$ $Total Pages = 50 \times 6 = 300$

Final Answer:

The total number of pages in the book is 300

Q177: Find the average of the series: 312, 162, 132, 142, and 122.

سیریز کی اوسط تلاش کریں: 312، 162، 132، 142، اور 122۔

162

174

186

194

Q178: The price of printer is Rs 150000 and is depreciated 4% annually. What is the price of printer after 3 years?

132710

131699

133766

None of these

Q179: The price of 2 x1/2 dozens eggs is Rs. 75. The price of one egg is:

Rs. 25

Rs. 0.25

Rs. 2.50

None of these

Explanation

Price of 2½ dozens eggs = Rs. 75
1 dozen = 12 eggs

So:

$2x 1 dozens = 2.5 \times 12 = 30 eggs$

Now find the price of one egg:

$text{Price of 1 egg} = frac{75}{30} = text{Rs. 2.50}$

Q180: 10a + 10b = 35, what is the average (arithmetic mean) of a and b?

10

7

3.5

1.75