Required marks in third examination = Total required marks in the three examinations - (Marks secured in first examination + Marks secured in second examination)

Correct Option: B

Total required marks in the three examinations = (3 x 600 x 70)/100 =1260

Marks secured in first examination = 55% of 600 = ( 600 x 55)/100 =330

Marks secured in second examination = 60% of 600 = ( 600 x 60)/100 =360

Thus, the required marks in third examination = 1260 - (330 + 360)
= 1260 - 690
= 570

Correct mean = ( sum of total marks - 57 + 75 ) / 30

Correct Option: D

Correct mean = ( sum of total marks - 57 + 75 ) / 30
= ( 30 x 58.5 - 57 + 75 ) / 30
= (1755 + 18 ) / 30
= 59.1

Monthly sale = yearly sale / 2

June's sale = monthly sale /2

Correct Option: C

Monthly sale = yearly sale / 2
= 132000 / 2
= ₹ 11000

June's sale = monthly sale / 2
= 11000 / 2
= ₹ 1000

Increased amount per month = 12000/12 = ₹ 1000

Correct Option: A

Total Income of the family per month
= 5 x 1000
= ₹ 5000

Increased amount per month = 12000/12 = ₹ 1000

Now, total amount of family income = ₹ 6000 per month

So, the average income of the family per month after increase = 6000/5
= ₹ 1200

Let the temperature on the last day of the week be x° C
Average of the week = ( 3 x 25 + 3 x 27 + x ) / 7 = 26.5

Correct Option: B

Let the temperature on the last day of the week be x° C

Average of the week = ( 3 x 25 + 3 x 27 + x ) / 7 = 26.5
⇒ 3 x 25 + 3 x 27 + x = 7 x 26.5
⇒ 156+ x = 185.5
∴ x = 29.5
So, the temprature on the last day of the week is 29.5° C