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Question 31

UPTET 2021• Mathematics and Science• Mathematics and Science

A company makes an advertisement of shares to collect a capital of Rs. 25 lacs. If the printed price of one share is Rs. 100, then find the number of shares circulated by the company.

  1. AOption (a)

    20000

  2. BOption (b)

    25000

  3. COption (c)

    30000

  4. DOption (d)

    15000

View answer & explanation

Correct answer

Answer: (b)B.

25000

Why this answer is correct

Given:

The total price of shares = Rs. 2500000

Price of one share = Rs. 100

Concept used:

Number of shares = Total price of shares/Price of one share

Calculation:

The total price of shares = Rs. 2500000

Price of one share = Rs. 100

Number of shares = Total price of shares/Price of one share

⇒ Number of shares = 2500000/100 = Rs. 25000

∴ The number of shares circulated by the company is 25000.

Question 32

UPTET 2021• Mathematics and Science• Mathematics and Science

From a pack of 52 playing cards, a card is drawn at random. What is the probability that the card is a spade or an ace?

  1. AOption (a)

    \(\dfrac{4}{13}\)

  2. BOption (b)

    \(\dfrac{6}{13}\)

  3. COption (c)

    \(\dfrac{8}{13}\)

  4. DOption (d)

    \(\dfrac{2}{5}\)

View answer & explanation

Correct answer

Answer: (a)A.

\(\dfrac{4}{13}\)

Why this answer is correct

Given:

Total number of cards = 52

Formula used:

Probability = Number of favorable outcome/ Total number of outcome

Calculation:

Total number of the spade in a standard deck of card = 13

Total number of aces in a standard deck of card = 4

Number of an ace in spade = 1

Number of favorable outcome = 13 + 4 – 1 = 16

Total number of outcome = 52

Probability = Number of favorable outcome/ total number of outcome

⇒ Probability = 16/52 = 4/13

∴ The probability that the card is a spade or an ace is 4/13.

Question 33

UPTET 2021• Mathematics and Science• Mathematics and Science

In the given figure, ABCD is a cyclic quadrilateral. Then the ordered pair (x, y) is

  1. AOption (a)

    (15°, 25°)  

  2. BOption (b)

    (10°, 15°)  

  3. COption (c)

    (15°, 35°)  

  4. DOption (d)

    (40°, 35°)  

View answer & explanation

Correct answer

Answer: (a)A.

(15°, 25°)  

Why this answer is correct

Given:

ABCD is a cyclic quadrilateral

∠ADC = 4y + 20°

∠ABC = 4x°

∠BAD = 3y – 5°

∠BCD = 7x + 5°

Concept used:

Sum of the opposite angle of a cyclic quadrilateral is 180°.

Calculation:

ABCD is a cyclic quadrilateral

∴ ∠ADC + ∠ABC = 180°

⇒ 4y + 20° + 4x° = 180°

⇒ x + y + 5° = 45°

⇒ x + y = 40°        ……(1)

And,

∠BAD + ∠BCD = 180°

⇒ 3y – 5° + 7x + 5° = 180°

⇒ 7x + 3y = 180°     …….(2)

Multiply 3 in equation (1) and subtract it in equation (2).

7x + 3y – 3x – 3y = 180° - 120°

⇒ 4x = 60°

⇒ x = 15°

Put value of x in equation (1)

x + y = 40°

⇒ 15° + y = 40°

⇒ y = 25°

∴ The ordered pair (x, y) is (15°, 25°).

Question 34

UPTET 2021• Mathematics and Science• Mathematics and Science

For what value of x, the mode of the following data is 27?

25, 26, 27, 23, 27, 26, 24, x, 27, 26, 25, 25

  1. AOption (a)

    27

  2. BOption (b)

    24

  3. COption (c)

    25

  4. DOption (d)

    26

View answer & explanation

Correct answer

Answer: (a)A.

27

Why this answer is correct

Given:

25, 26, 27, 23, 27, 26, 24, x, 27, 26, 25, 25

Concept used:

The mode is the value that appears most often in a set of data values.

Calculation:

Following data is arranged in ascending order:

23, 24, 25, 25, 25, 26, 26, 26, 27, 27, 27, x.

The number of repetitions in data.

23 and 24 - 1 time

25 and 26 - 3 times

27 - 3 times

If Mode = 27

i.e., 27 appears most often (4 times) in given sets of data values.

∴ x = 27

Question 35

UPTET 2021• Mathematics and Science• Mathematics and Science

If x = 2, y = 1, z = -3 then x3 + y3 + z3 - 3xyz equals

  1. AOption (a)

    6

  2. BOption (b)

    2

  3. COption (c)

    8

  4. DOption (d)

    0

View answer & explanation

Correct answer

Answer: (d)D.

0

Why this answer is correct

Given:

x = 2, y = 1, z = -3

Formula used:

x3 + y3 + z3 – 3xyz = (x + y + z)(x2 + y2 + z2 – xy – yz – zx)

Calculation:

x + y + z = 2 + 1 + (-3) = 3 – 3 = 0

If x + y + z = 0,

Then x3 + y3 + z3 – 3xyz = 0

∴ x3 + y3 + z3 – 3xyz = 0.

Question 36

UPTET 2021• Mathematics and Science• Mathematics and Science

Jatin buys an article for 10% less than its value and sells it for 10% more than its value. His gain is

  1. AOption (a)

    20%

  2. BOption (b)

    \(22 \dfrac{7}{9}%\)

  3. COption (c)

    \(22 \dfrac{2}{9}%\)

  4. DOption (d)

    None of the above

View answer & explanation

Correct answer

Answer: (c)C.

\(22 \dfrac{2}{9}%\)

Why this answer is correct

Given:

Jatin buys an article for 10% less than its value

sells it for 10% more than its value

Formula used:

Profit% = [(S.P – C.P)/C.P] × 100

Calculation:

Let original value be Rs. 10

He bought it at = Rs. 10 × (90/100) = Rs. 90

He sells it at = Rs. 10 × (110/100) = Rs. 110

Gain = Rs. 110 – Rs. 90 = Rs. 20

Gain% = (20/90) × 100%

⇒ 200/9% = \(22\frac{2}{9}\)%

∴ The gain percentage is \(22\frac{2}{9}\)%

Question 37

UPTET 2021• Mathematics and Science• Mathematics and Science

If the roots of the equation x2 - px + 54 = 0 are in the ratio 2 ∶ 3, then the value of p is

  1. AOption (a)

    18

  2. BOption (b)

    51

  3. COption (c)

    -21

  4. DOption (d)

    15

View answer & explanation

Correct answer

Answer: (d)D.

15

Why this answer is correct

Basic quadratic equation is ax2 + bx + c  where sum of roots =-b/a and product of roots = c/a

⇒ Here two roots be α and β which are 2x and 3x.

⇒ α × β = c/a  

⇒ α × β = 54

⇒ 6x2 = 54

⇒ x = 3 so α = 6 and β = 9

⇒ Now sum of roots = α + β = -b/a 

⇒ p = 15

Question 38

UPTET 2021• Mathematics and Science• Mathematics and Science

The ratio of the heights of two right circular cones is 25 ∶ 64 and the ratio of their diameters is 4 ∶ 5. The ratio of their volumes is

  1. AOption (a)

    1 ∶ 3 

  2. BOption (b)

    1 ∶ 4

  3. COption (c)

    5 ∶ 8

  4. DOption (d)

    1 ∶ 2

View answer & explanation

Correct answer

Answer: (b)B.

1 ∶ 4

Why this answer is correct

Given:  

The ratio of the heights of the two right circular cones and their diameters is given.

Formula used:

The volume of cone = \(\frac{1}{3}\pi {r^2}h\)

Calculation:

Here we have two cones with two different radius and height.

Let the radius and the height of the first cone be r1 and h1. Similarly the radius and the height of the second cone be r2 and h2.

Volume of the first cone be \(\frac{1}{3}\pi {r_1}^2{h_1}\) and the volume of the second cone be \(\frac{1}{3}\pi {r_2}^2{h_2}\)

⇒ r1 = 2 and r2 = 2.5, h1 = 25 and h2 = 64

⇒ placing the above value in the equation \(\frac{{\frac{1}{3}\pi {r_1}^2{h_1}}}{{\frac{1}{3}\pi {r_2}^2{h_2}}}\)

⇒ \(\frac{{\pi {r_1}^2{h_1}}}{{\pi {r_2}^2{h_2}}}\) = \(\frac{{4 \times 25}}{{6.25 \times 64}}\) = \(\frac{1}{4}\)

∴ Required ratio = 1: 4

Question 39

UPTET 2021• Mathematics and Science• Mathematics and Science

If A = {x ∶ x is a letter in word BELOW}, B = {x ∶ x is a letter in word WOOL} and C = A – B, then the number of subsets of C is

  1. AOption (a)

    1

  2. BOption (b)

    2

  3. COption (c)

    3

  4. DOption (d)

    4

View answer & explanation

Correct answer

Answer: (d)D.

4

Why this answer is correct

Given: 

A = {BELOW}, B = {WOOL}

Concept used:

If a set has “n” elements, then the number of subset of the given set is 2n

Calculation:

⇒ C = A – B

⇒ C = {B, E} taking out the common letters.

The subsets of C = 22 = 4

∴ The number of subsets of C is 4

Question 40

UPTET 2021• Mathematics and Science• Mathematics and Science

The perimeter of a rhombus whose diagonals are 10 cm and 24 cm is

  1. AOption (a)

    120 cm

  2. BOption (b)

    34 cm

  3. COption (c)

    68 cm

  4. DOption (d)

    52 cm

View answer & explanation

Correct answer

Answer: (d)D.

52 cm

Why this answer is correct

Given:

Diagonals BD = 24 and AC = 10.

Concept used: 

Rhombus has all four sides equal and their diagonals bisect each other at 90° 

Let both the diagonals meet at O,

OD = OB = 12 and AO = OC = 5

In Δ OCD use the Pythagoras theorem.

In Δ OCD, OD2 + OC2 = DC2 ,

122 + 52 = DC2

⇒ DC = 13

The perimeter of the Rhombus is 4a where a is the sides of the rhombus.

∴ Perimeter = 4 × 13 = 52 cm.