The correct answer is option 3 i.e. 12 km/h.

Average Speed = 2 × Distance₁ × Distance₂ / Distance₁ + Distance₂

D = 20 km 

Time taken to go  = D / 20 = 1  hour 

Time returning = D / v

Total Time = 1 + D / v = 1 + 20 / v

⇒ 15 = (40) / (1 + 20 / v)

⇒ 15 (1 + 20 / v )= 40

⇒ 15 + 300 / v= 40

⇒ 300 / v = 25

⇒ 300 = 25v

v = 12  km/h

The correct answer is Option 1 i.e. 108.

As per the given question,

⇒ 1st number = 2x (let)

⇒ 2nd number = 3(2x) = 6x

⇒ 3rd number = 6x/2 = 3x

We know that,

Average = Sum of observations/Number of observations

⇒ (2x + 6x + 3x)/3 = 66

⇒ 11x = 66 × 3

⇒ x = 6 × 3

⇒ x = 18

2nd number = 3(2x) = 3(2 × 18) = 108

The correct answer is option 2 i.e. 15:14.

Given that

The ratio of the number of marbles that Joyee and Minati had was 5 : 8

the ratio of the number of marbles that Jacob and Minati had was 7 : 12

According to the question

Joyee/Minati = 5x/8x ...........(1

Jacob/Minati = 7x/12x  ........(2

Now, Joyee/Jacob = (5x/8x)/(7x/12x) = 5/8 × 12/7 = 15/14

Hence, the ratio of Joyee and Jacob is 15 : 14

The correct answer is option 4 i.e. ₹300.

Given that

Principal (P) =  ₹ 1250

Time (T) = 6 years

Rate of simple interest (R) = 4% p.a.

Formula used:

S.I. = P × R × T/100

where, S.I. = Simple interest, P = Principal, T = time

Calculation:

S.I. = 1250 × 4 × 6/100 

S.I. = 50 × 6

S.I. = ₹ 300

The correct answer is option 3 i.e. 50.

⇒ salary drawn by highest paid CEO = 75 lakh

⇒ salary drawn by lowest paid CEO = 50 lakh

⇒ Difference between these salaries = 75 lakh - 50 lakh = 25 lakh

⇒ Difference Percentage = 25/50 × 100 = 50 %

The correct answer is option 1 i.e. 140°.

∠ A = 40° , ∠ B = 70°

∠ C  = 180° - ∠A - ∠ B = 180° - 40° - 70° = 70°

Exterior  ∠ A = ∠ B + ∠ C = 70° + 70°= 140°

The correct answer is Option 4 i.e. Rs 19200.

Lateral surface = 2h (l + b)

⇒ 2 × 3 × (6 + 4) = 60 m²

Cost of painting = 60 × 320

⇒ Rs 19200

The correct answer is option 3 i.e. 45/4.

 5sin²60° + 7sin²45° + 8cos²45°

= 5 × (√3/2)² + 7 × (1/√2)² + 8 × (1/√2)²

= 5 × (3/4) + 7 × (1/2) + 8 × (1/2)

= (15/4) + (7/2) + (8/2)

= (45/4)

The correct answer is option 3 i.e. 2/3.

cosec(- 45°) + sec (π/2 - 45°) - sin(- 90°) - tan²(- 30°)

We know that

⇒ cosec(- θ) = - cosecθ

⇒ sec(90 - θ) = cosecθ

⇒ sin(- θ) = - sinθ and,

⇒ tan(- θ) = - tanθ

Now, according to the question 

⇒ - cosec 45° + cosec 45° - (-sin 90°) - tan² 30°

⇒ -(-1) - 1/3

⇒ 1 - (1/3) = 2/3

The correct answer is Option 4 i.e. Rs. 4400.

Selling price = Cost price (1 - Loss %)

Selling price = Cost price (1 + Profit %)

Let the cost price of the television = Rs. X

Selling Price (SP) = Cost Price (1 - 10 %) = X [1 - (10/100)]

= 90X/100

If the shopkeeper had instead sold the television for Rs. 1540 more, he would have made 25% profit
(i.e)

SP + 1540 = X + (25/100) X

⇒ (90X/100) + 1540 = (125X/100)

⇒ (125X/100) - (90X/100) = 1540

⇒ 35X/100 = 1540

⇒ X = (1540 × 100)/35 = Rs. 4400